[lit] Improve test output from lit's internal shell

[jdenny]

Summary

This patch and D154984 were discussed in https://discourse.llvm.org/t/rfc-improving-lits-debug-output/72839.

Motivation

D154984 removes the "Script:" section that lit prints along with a test's output, and it makes -v and -a imply -vv. For example, after D154984, the "Script:" section below is never shown, but -v is enough to produce the execution trace following it:

Script:
--
: 'RUN: at line 1'; echo hello | FileCheck bogus.txt && echo success
--
Exit Code: 2

Command Output (stdout):
--
$ ":" "RUN: at line 1"
$ "echo" "hello"
# command output:
hello

$ "FileCheck" "bogus.txt"
# command stderr:
Could not open check file 'bogus.txt': No such file or directory

error: command failed with exit status: 2

--

In the D154984 review, some reviewers point out that they have been using the "Script:" section for copying and pasting a test's shell commands to a terminal window. The shell commands as printed in the execution trace can be harder to copy and paste for the following reasons:

• They drop redirections and break apart RUN lines at &&, |, etc.
• They add $ at the start of every command, which makes it hard to copy and paste multiple commands in bulk.
• Command stdout, stderr, etc. are interleaved with the commands and are not clearly delineated.
• They don't always use proper shell quoting. Instead, they blindly enclose all command-line arguments in double quotes.

Changes

D154984 plus this patch converts the above example into:

Exit Code: 2

Command Output (stdout):
--
# RUN: at line 1
echo hello | FileCheck bogus-file.txt && echo success
# executed command: echo hello
# .---command stdout------------
# | hello
# `-----------------------------
# executed command: FileCheck bogus-file.txt
# .---command stderr------------
# | Could not open check file 'bogus-file.txt': No such file or directory
# `-----------------------------
# error: command failed with exit status: 2

--

Thus, this patch addresses the above issues as follows:

• The entire execution trace can be copied and pasted in bulk to a terminal for correct execution of the RUN lines, which are printed intact as they appeared in the original RUN lines except lit substitutions are expanded. Everything else in the execution trace appears in shell comments so it has no effect in a terminal.
• Each of the RUN line's commands is repeated (in shell comments) as it executes to show (1) that the command actually executed (e.g., echo success above didn't) and (2) what stdout, stderr, non-zero exit status, and output files are associated with the command, if any. Shell quoting in the command is now correct and minimal but is not necessarily the original shell quoting from the RUN line.
• The start and end of the contents of stdout, stderr, or an output file is now delineated clearly in the trace.

To help produce some of the above output, this patch extends lit's internal shell with a built-in @echo command. It's like echo except lit suppresses the normal execution trace for @echo and just prints its stdout directly. For now, @echo isn't documented for use in lit tests.

Without this patch, libcxx's custom lit test format tries to parse the stdout from lit.TestRunner.executeScriptInternal (which runs lit's internal shell) to extract the stdout and stderr produced by shell commands, and that parse no longer works after the above changes. This patch makes a small adjustment to lit.TestRunner.executeScriptInternal so libcxx can just request stdout and stderr without an execution trace.

(As a minor drive-by fix that came up in testing: lit's internal not command now always produces a numeric exit status and never True.)

Caveat

This patch only makes the above changes for lit's internal shell. In most cases, we do not know how to force external shells (e.g., bash, sh, window's cmd) to produce execution traces in the manner we want.

To configure a test suite to use lit's internal shell (which is usually better for test portability than external shells anyway), add this to the test suite's lit.cfg or other configuration file:

config.test_format = lit.formats.ShTest(execute_external=False)

[MaskRay]

Thank you for the nice summary! I just read the internal implementation the other day and glanced at the change. This change is reasonable and the test coverage looks great.
The new built-in @echo probably should be mentioned in the summary/commit message as well.

[jdenny]

Rebased.

[jdenny]

In D156954#4558080, @MaskRay wrote:

Thank you for the nice summary! I just read the internal implementation the other day and glanced at the change. This change is reasonable and the test coverage looks great.

Thanks for the review.

In case anyone missed it, before this lands, we'll need consensus on D154984, and there was a request to do an RFC for that purpose. I wanted to have this patch to address concerns about D154984 first.

The new built-in @echo probably should be mentioned in the summary/commit message as well.

Good idea. Done.

[awarzynski]

Thank you so much! This fully addresses the concerns that I raised in https://reviews.llvm.org/D154984.

[jdenny]

Improve test coverage for new behavior. Fix issues that revealed:

• Drive-by fix that came up in testing: internal not cmd sometimes produced exit status of True. Fixed that to be 1.
• Instead of # command line, add # preamble command line before command lines from preamble_commands.
• When expanding %dbg(...), don't modify the original script. Otherwise, upon every retry (due to ALLOW_RETRIES), we keep prepending the generic # command line to it as if there was no %dbg(...).
• Assert that %dbg(...) is never missing. ninja check-lit doesn't fail this assert. CI testing will hopefully answer this question for all other uses.
• If @echo has any unexpected results, instead of failing a generic assertion and losing the specific diagnostic, enable the normal execution trace as if it's echo.

[jdenny]

In D156954#4564171, @awarzynski wrote:

Thank you so much! This fully addresses the concerns that I raised in https://reviews.llvm.org/D154984.

Thanks for confirming.

[jdenny]

D154987's pre-commit CI discovered that libcxx's custom lit test format doesn't always use %dbg(...) on commands. Chances are that there are other test suites in the same boat. Eliminate the associated assertion and todo in this patch.

[jdenny]

D154987's pre-commit CI revealed another issue with libcxx. This update tries to fix that. See changes to the patch summary for details.

Now that libcxx is modified by this patch, we should see any additional libcxx pre-commit CI failures here. I've tried to run check-cxx on my machine, but it takes hours, and many tests are expected fails or excluded, so I've only checked some cases.

Sorry for the churn.

[jdenny]

The requested RFC for D154984 and D156954: https://discourse.llvm.org/t/rfc-improving-lits-debug-output/72839

[jdenny]

I saw only one bit of feedback from the RFC that affects this patch. That is, theoretically, a windows user might wish to adjust the shell comment sequence that lit's internal shell uses in its execution trace. This feature might help with copying multiple command lines at once from that trace and pasting them into any of the various shells that people use in windows. However, people seemed fine to wait to do that in a separate patch if an actual user who cares about that use case speaks up.

At this point, I think we're just waiting on D154984 to be accepted.

@ldionne In the meantime, if it hasn't happened already, it might be good for a libcxx person to review the libcxx changes in this patch.

[awarzynski]

LGTM, thank you for addressing my comments!

[dyung]

@jdenny I am the owner of the llvm-clang-x86_64-sie-win bot, let me know if you need any help to fix the failures from your change.

[jdenny]

In D156954#4625928, @dyung wrote:

@jdenny I am the owner of the llvm-clang-x86_64-sie-win bot, let me know if you need any help to fix the failures from your change.

Thanks for pinging me, and sorry for all the trouble. I think I nearly have a final fix and expect to push within a few minutes.

[dyung]

In D156954#4626012, @jdenny wrote:

In D156954#4625928, @dyung wrote:

@jdenny I am the owner of the llvm-clang-x86_64-sie-win bot, let me know if you need any help to fix the failures from your change.

Thanks for pinging me, and sorry for all the trouble. I think I nearly have a final fix and expect to push within a few minutes.

Getting close, the last failure just seems to be due to the path separators '/' vs. '\' being explicitly checked for.

[jdenny]

In D156954#4626071, @dyung wrote:

Getting close, the last failure just seems to be due to the path separators '/' vs. '\' being explicitly checked for.

Yes. By now, I really ought to remember that one when writing tests.

OK, I landed these additional commits to fix various issues (shell quoting and / vs \) in lit tests running in windows:

• f254bbf23374190c88a2b1a5f163622fbec9a936
• 3db5db92d746bad8ba1762ca290a176e25d48565
• 012d844fb856a89368aca95ca994726554b90f22
• b6bd9d275f783f8150c8a04145ef2a31edb4fddf

Those commits fix lit's tests but do not change lit itself. See the commit logs there for details.

Sorry it took me a while.

In D156954#4625928, @dyung wrote:

@jdenny I am the owner of the llvm-clang-x86_64-sie-win bot, let me know if you need any help to fix the failures from your change.

One thing all bot maintainers might consider doing is adding the following to the environment:

export FILECHECK_OPTS='-dump-input-filter=all -vv -color'

As discussed in f254bbf23374190c88a2b1a5f163622fbec9a936, this provides a lot more info for debugging test fails. For the sake of users running tests locally who want less verbose output, it's not the FileCheck default. However, it's easy for them to run again with the above when needed. It's not easy to do that for CI on a system you don't own.

(Of course, you might drop -color if color doesn't render well.)

Just a suggestion.

[Mordante]

I see some feedback on Windows build issues and some followups. Yesterday libc++'s precommit CI for Windows started to fail, the first build is https://buildkite.com/llvm-project/libcxx-ci/builds/29307

This is the relevant part of the log

C:\Users\ContainerAdministrator\AppData\Local\Temp\buildkite-script-1445266630.bat
+ set -o pipefail
+ unset LANG
+ unset LC_ALL
+ unset LC_COLLATE
++ basename libcxx/utils/ci/run-buildbot
+ PROGNAME=run-buildbot
+ [[ 1 == 0 ]]
+ [[ 1 -gt 0 ]]
+ case ${1} in
+ BUILDER=clang-cl-dll
+ shift
+ [[ 0 -gt 0 ]]
++ git rev-parse --show-toplevel
+ MONOREPO_ROOT=C:/ws/src
+ BUILD_DIR=C:/ws/src/build/clang-cl-dll
+ INSTALL_DIR=C:/ws/src/build/clang-cl-dll/install
+ xcrun --find ninja
+ which ninja
++ which ninja
+ NINJA=/c/ProgramData/chocolatey/bin/ninja
+ '[' -z '' ']'
+ xcrun --find cmake
+ CMAKE=cmake
+ '[' -z '' ']'
+ ENABLE_CLANG_TIDY=Off
+ '[' -n '' ']'
+ cmake --version
libcxx/utils/ci/run-buildbot: line 195: cmake: command not found
🚨 Error: The command exited with status 127
user command error: exit status 127

Could this be caused by your changes?

[mstorsjo]

In D156954#4627295, @Mordante wrote:

I see some feedback on Windows build issues and some followups. Yesterday libc++'s precommit CI for Windows started to fail, the first build is https://buildkite.com/llvm-project/libcxx-ci/builds/29307

This is the relevant part of the log

+ cmake --version
libcxx/utils/ci/run-buildbot: line 195: cmake: command not found
🚨 Error: The command exited with status 127
user command error: exit status 127

Could this be caused by your changes?

I doubt that's related - that error happens before execution even reaches any part of the lit scripts. I would bring this up with @goncharov - it seems like the base image on the runners has been updated to one that doesn't have cmake available (or in $PATH).

[jdenny]

In D156954#4627613, @mstorsjo wrote:

I doubt that's related

Agreed. Thanks.

[Mordante]

In D156954#4627613, @mstorsjo wrote:

In D156954#4627295, @Mordante wrote:

I see some feedback on Windows build issues and some followups. Yesterday libc++'s precommit CI for Windows started to fail, the first build is https://buildkite.com/llvm-project/libcxx-ci/builds/29307

This is the relevant part of the log

+ cmake --version
libcxx/utils/ci/run-buildbot: line 195: cmake: command not found
🚨 Error: The command exited with status 127
user command error: exit status 127

Could this be caused by your changes?

I doubt that's related - that error happens before execution even reaches any part of the lit scripts. I would bring this up with @goncharov - it seems like the base image on the runners has been updated to one that doesn't have cmake available (or in $PATH).

Was not certain, but since it was just after the patch landed and there were followups for Windows and I didn't look at all of them. I'll ask @goncharov.

[jdenny]

Rebased onto the most recent version of D154984.

Due to the changes from the current patch, updated expected results in a few lit tests brought in by the above rebase.

Adjusted lit's -v docs not to talk about no-op commands like : because this patch changes lit's internal shell not to use that. PR #65267 (edit: that's now PR #66408) proposes to change support for external sh-like shells similarly.

Folded in all fixup commits that I landed when trying to land this patch the first time. They were all tweaks in lit's test suite for portability to windows:

• f254bbf23374190c88a2b1a5f163622fbec9a936
• 3db5db92d746bad8ba1762ca290a176e25d48565
• 012d844fb856a89368aca95ca994726554b90f22
• b6bd9d275f783f8150c8a04145ef2a31edb4fddf

Applied python formatting suggestions from darker.

I don't think this patch requires another review before I land it, but of course reviewers are welcome to comment. I will wait to re-land it along with PR #65267 (edit: that's now PR #66408), which still requires more work and review.

libcxx/utils/libcxx/test/dsl.py

with _makeConfigTest(config) as test:
         out, err, exitCode, _, runcmd = _executeWithFakeConfig(
             test, ["%{{run}} {}".format(" ".join(args))]
         )
         if exitCode != 0:
             raise ConfigurationRuntimeError(
                 "Failed to run program, cmd:\n{}\nstderr is:\n{}".format(runcmd, err)
             )
 
-        return libcxx.test.format._parseLitOutput(out)
+        return out
 
 
 @_memoizeExpensiveOperation(
     lambda c, p, args=None: (c.substitutions, c.environment, p, args)
 )
 def programSucceeds(config, program, args=None):
     """
     Compiles a program for the test target, run it on the test target and return

libcxx/utils/libcxx/test/format.py

def _getTempPaths(test):
     return tmpDir, tmpBase
 
 
 def _checkBaseSubstitutions(substitutions):
     substitutions = [s for (s, _) in substitutions]
     for s in ["%{cxx}", "%{compile_flags}", "%{link_flags}", "%{flags}", "%{exec}"]:
         assert s in substitutions, "Required substitution {} was not provided".format(s)
 
-def _parseLitOutput(fullOutput):
-    """
-    Parse output of a Lit ShTest to extract the actual output of the contained commands.
-
-    This takes output of the form
-
-        $ ":" "RUN: at line 11"
-        $ "echo" "OUTPUT1"
-        # command output:
-        OUTPUT1
-
-        $ ":" "RUN: at line 12"
-        $ "echo" "OUTPUT2"
-        # command output:
-        OUTPUT2
-
-    and returns a string containing
-
-        OUTPUT1
-        OUTPUT2
-
-    as-if the commands had been run directly. This is a workaround for the fact
-    that Lit doesn't let us execute ShTest and retrieve the raw output without
-    injecting additional Lit output around it.
-    """
-    parsed = ''
-    for output in re.split('[$]\s*":"\s*"RUN: at line \d+"', fullOutput):
-        if output: # skip blank lines
-            commandOutput = re.search("# command output:\n(.+)\n$", output, flags=re.DOTALL)
-            if commandOutput:
-                parsed += commandOutput.group(1)
-    return parsed
-
 def _executeScriptInternal(test, litConfig, commands):
     """
     Returns (stdout, stderr, exitCode, timeoutInfo, parsedCommands)
 
     TODO: This really should be easier to access from Lit itself
     """
     parsedCommands = parseScript(test, preamble=commands)
 
     _, tmpBase = _getTempPaths(test)
     execDir = os.path.dirname(test.getExecPath())
     res = lit.TestRunner.executeScriptInternal(
-        test, litConfig, tmpBase, parsedCommands, execDir
+        test, litConfig, tmpBase, parsedCommands, execDir, debug=False
     )
     if isinstance(res, lit.Test.Result):  # Handle failure to parse the Lit test
         res = ("", res.output, 127, None)
     (out, err, exitCode, timeoutInfo) = res
 
-    # TODO: As a temporary workaround until https://reviews.llvm.org/D81892 lands, manually
-    #       split any stderr output that is included in stdout. It shouldn't be there, but
-    #       the Lit internal shell conflates stderr and stdout.
-    conflatedErrorOutput = re.search("(# command stderr:.+$)", out, flags=re.DOTALL)
-    if conflatedErrorOutput:
-        conflatedErrorOutput = conflatedErrorOutput.group(0)
-        out = out[: -len(conflatedErrorOutput)]
-        err += conflatedErrorOutput
-
     return (out, err, exitCode, timeoutInfo, parsedCommands)
 
 
 def parseScript(test, preamble):
     """
     Extract the script from a test, with substitutions applied.
 
     Returns a list of commands ready to be executed.
def _generateGenTest(self, testSuite, pathInSuite, litConfig, localConfig):
 
         # Run the generator test
         steps = [] # Steps must already be in the script
         (out, err, exitCode, _, _) = _executeScriptInternal(generator, litConfig, steps)
         if exitCode != 0:
             raise RuntimeError(f"Error while trying to generate gen test\nstdout:\n{out}\n\nstderr:\n{err}")
 
         # Split the generated output into multiple files and generate one test for each file
-        parsed = _parseLitOutput(out)
-        for (subfile, content) in self._splitFile(parsed):
-            generatedFile = testSuite.getExecPath(pathInSuite + (subfile, ))
+        for subfile, content in self._splitFile(out):
+            generatedFile = testSuite.getExecPath(pathInSuite + (subfile,))
             os.makedirs(os.path.dirname(generatedFile), exist_ok=True)
             with open(generatedFile, 'w') as f:
                 f.write(content)
             yield lit.Test.Test(testSuite, (generatedFile,), localConfig)
 
     def _splitFile(self, input):
         DELIM = r'^(//|#)---(.+)'
         lines = input.splitlines()

llvm/docs/CommandGuide/lit.rst

 
 .. option:: -v, --verbose
 
  Show more information on test failures, for example the entire test output
  instead of just the test result.
 
  Each command is printed before it is executed. This can be valuable for
  debugging test failures, as the last printed command is the one that failed.
- Moreover, :program:`lit` inserts a no-op command (``:`` in the case of bash)
- with argument ``'RUN: at line N'`` before each command pipeline, and those
- no-op commands are also printed to help you locate the source line of the
- failed command.
+ Moreover, :program:`lit` inserts ``'RUN: at line N'`` before each
+ command pipeline in the output to help you locate the source line of
+ the failed command.
 
 .. option:: -vv, --echo-all-commands
 
  Deprecated alias for -v.
 
 .. option:: -a, --show-all
 
  Enable -v, but for all tests not just failed tests.

llvm/utils/lit/lit/TestRunner.py

 from __future__ import absolute_import
 import errno
 import io
 import itertools
 import getopt
 import os, signal, subprocess, sys
 import re
 import stat
 import pathlib
 import platform
+import shlex
 import shutil
 import tempfile
 import threading
 
 import io
 
 try:
     from StringIO import StringIO
def executeBuiltinExport(cmd, shenv):
     """executeBuiltinExport - Set an environment variable."""
     if len(cmd.args) != 2:
         raise InternalShellError("'export' supports only one argument")
     updateEnv(shenv, cmd.args)
     return ShellCommandResult(cmd, "", "", 0, False)
 
 
 def executeBuiltinEcho(cmd, shenv):
-    """Interpret a redirected echo command"""
+    """Interpret a redirected echo or @echo command"""
     opened_files = []
     stdin, stdout, stderr = processRedirects(cmd, subprocess.PIPE, shenv, opened_files)
     if stdin != subprocess.PIPE or stderr != subprocess.PIPE:
         raise InternalShellError(
-            cmd, "stdin and stderr redirects not supported for echo"
+            cmd, f"stdin and stderr redirects not supported for {cmd.args[0]}"
         )
 
     # Some tests have un-redirected echo commands to help debug test failures.
     # Buffer our output and return it to the caller.
     is_redirected = True
     encode = lambda x: x
     if stdout == subprocess.PIPE:
         is_redirected = False
def _executeShCmd(cmd, shenv, results, timeoutHelper):
     builtin_commands = set(["cat", "diff"])
     builtin_commands_dir = os.path.join(
         os.path.dirname(os.path.abspath(__file__)), "builtin_commands"
     )
     inproc_builtins = {
         "cd": executeBuiltinCd,
         "export": executeBuiltinExport,
         "echo": executeBuiltinEcho,
+        "@echo": executeBuiltinEcho,
         "mkdir": executeBuiltinMkdir,
         "popd": executeBuiltinPopd,
         "pushd": executeBuiltinPushd,
         "rm": executeBuiltinRm,
         ":": executeBuiltinColon,
     }
     # To avoid deadlock, we use a single stderr stream for piped
     # output. This is null until we have seen some output using
def _executeShCmd(cmd, shenv, results, timeoutHelper):
 
     exitCode = None
     for i, (out, err) in enumerate(procData):
         res = procs[i].wait()
         # Detect Ctrl-C in subprocess.
         if res == -signal.SIGINT:
             raise KeyboardInterrupt
         if proc_not_counts[i] % 2:
-            res = not res
+            res = 1 if res == 0 else 0
         elif proc_not_counts[i] > 1:
             res = 1 if res != 0 else 0
 
         # Ensure the resulting output is always of string type.
         try:
             if out is None:
                 out = ""
             else:
for f in named_temp_files:
             pass
 
     if cmd.negate:
         exitCode = not exitCode
 
     return exitCode
 
 
-def executeScriptInternal(test, litConfig, tmpBase, commands, cwd):
+def formatOutput(title, data, limit=None):
+    if not data.strip():
+        return ""
+    if not limit is None and len(data) > limit:
+        data = data[:limit] + "\n...\n"
+        msg = "data was truncated"
+    else:
+        msg = ""
+    ndashes = 30
+    # fmt: off
+    out =  f"# .---{title}{'-' * (ndashes - 4 - len(title))}\n"
+    out += f"# | " + "\n# | ".join(data.splitlines()) + "\n"
+    out += f"# `---{msg}{'-' * (ndashes - 4 - len(msg))}\n"
+    # fmt: on
+    return out
+
+
+# Normally returns out, err, exitCode, timeoutInfo.
+#
+# If debug is True (the normal lit behavior), err is empty, and out contains an
+# execution trace, including stdout and stderr shown per command executed.
+#
+# If debug is False (set by some custom lit test formats that call this
+# function), out contains only stdout from the script, err contains only stderr
+# from the script, and there is no execution trace.
+def executeScriptInternal(test, litConfig, tmpBase, commands, cwd, debug=True):
     cmds = []
     for i, ln in enumerate(commands):
+        # Within lit, we try to always add '%dbg(...)' to command lines in order
+        # to maximize debuggability.  However, custom lit test formats might not
+        # always add it, so add a generic debug message in that case.
         match = re.fullmatch(kPdbgRegex, ln)
         if match:
+            dbg = match.group(1)
             command = match.group(2)
-            ln = commands[i] = match.expand(": '\\1'; \\2" if command else ": '\\1'")
+        else:
+            dbg = "command line"
+            command = ln
+        if debug:
+            ln = f"@echo '# {dbg}' "
+            if command:
+                ln += f"&& @echo {shlex.quote(command.lstrip())} && {command}"
+            else:
+                ln += "has no command after substitutions"
+        else:
+            ln = command
         try:
             cmds.append(
                 ShUtil.ShParser(ln, litConfig.isWindows, test.config.pipefail).parse()
             )
         except:
-            return lit.Test.Result(Test.FAIL, "shell parser error on: %r" % ln)
+            return lit.Test.Result(
+                Test.FAIL, f"shell parser error on {dbg}: {command.lstrip()}\n"
+            )
 
     cmd = cmds[0]
     for c in cmds[1:]:
         cmd = ShUtil.Seq(cmd, "&&", c)
 
     results = []
     timeoutInfo = None
     try:
         shenv = ShellEnvironment(cwd, test.config.environment)
         exitCode, timeoutInfo = executeShCmd(
             cmd, shenv, results, timeout=litConfig.maxIndividualTestTime
         )
     except InternalShellError:
         e = sys.exc_info()[1]
         exitCode = 127
         results.append(ShellCommandResult(e.command, "", e.message, exitCode, False))
 
     out = err = ""
     for i, result in enumerate(results):
-        # Write the command line run.
-        out += "$ %s\n" % (" ".join('"%s"' % s for s in result.command.args),)
+        if not debug:
+            out += result.stdout
+            err += result.stderr
+            continue
+
+        # The purpose of an "@echo" command is merely to add a debugging message
+        # directly to lit's output.  It is used internally by lit's internal
+        # shell and is not currently documented for use in lit tests.  However,
+        # if someone misuses it (e.g., both "echo" and "@echo" complain about
+        # stdin redirection), produce the normal execution trace to facilitate
+        # debugging.
+        if (
+            result.command.args[0] == "@echo"
+            and result.exitCode == 0
+            and not result.stderr
+            and not result.outputFiles
+            and not result.timeoutReached
+        ):
+            out += result.stdout
+            continue
+
+        # Write the command line that was run.  Properly quote it.  Leading
+        # "!" commands should not be quoted as that would indicate they are not
+        # the builtins.
+        out += "# executed command: "
+        nLeadingBangs = next(
+            (i for i, cmd in enumerate(result.command.args) if cmd != "!"),
+            len(result.command.args),
+        )
+        out += "! " * nLeadingBangs
+        out += " ".join(
+            shlex.quote(str(s))
+            for i, s in enumerate(result.command.args)
+            if i >= nLeadingBangs
+        )
+        out += "\n"
 
         # If nothing interesting happened, move on.
         if (
             litConfig.maxIndividualTestTime == 0
             and result.exitCode == 0
             and not result.stdout.strip()
             and not result.stderr.strip()
         ):
             continue
 
         # Otherwise, something failed or was printed, show it.
 
         # Add the command output, if redirected.
         for (name, path, data) in result.outputFiles:
-            if data.strip():
-                out += "# redirected output from %r:\n" % (name,)
-                data = to_string(data.decode("utf-8", errors="replace"))
-                if len(data) > 1024:
-                    out += data[:1024] + "\n...\n"
-                    out += "note: data was truncated\n"
-                else:
-                    out += data
-                out += "\n"
-
+            out += formatOutput(f"redirected output from '{name}'", data, limit=1024)
         if result.stdout.strip():
-            out += "# command output:\n%s\n" % (result.stdout,)
+            out += formatOutput("command stdout", result.stdout)
         if result.stderr.strip():
-            out += "# command stderr:\n%s\n" % (result.stderr,)
+            out += formatOutput("command stderr", result.stderr)
         if not result.stdout.strip() and not result.stderr.strip():
-            out += "note: command had no output on stdout or stderr\n"
+            out += "# note: command had no output on stdout or stderr\n"
 
         # Show the error conditions:
         if result.exitCode != 0:
             # On Windows, a negative exit code indicates a signal, and those are
             # easier to recognize or look up if we print them in hex.
             if litConfig.isWindows and (result.exitCode < 0 or result.exitCode > 255):
                 codeStr = hex(int(result.exitCode & 0xFFFFFFFF)).rstrip("L")
             else:
                 codeStr = str(result.exitCode)
-            out += "error: command failed with exit status: %s\n" % (codeStr,)
+            out += "# error: command failed with exit status: %s\n" % (codeStr,)
         if litConfig.maxIndividualTestTime > 0 and result.timeoutReached:
-            out += "error: command reached timeout: %s\n" % (
+            out += "# error: command reached timeout: %s\n" % (
                 str(result.timeoutReached),
             )
 
     return out, err, exitCode, timeoutInfo
 
 
 def executeScript(test, litConfig, tmpBase, commands, cwd):
     bashPath = litConfig.getBashPath()

 
 def executeShTest(
     test, litConfig, useExternalSh, extra_substitutions=[], preamble_commands=[]
 ):
     if test.config.unsupported:
         return lit.Test.Result(Test.UNSUPPORTED, "Test is unsupported")
 
     script = list(preamble_commands)
+    script = [buildPdbgCommand(f"preamble command line", ln) for ln in script]
+
     parsed = parseIntegratedTestScript(test, require_script=not script)
     if isinstance(parsed, lit.Test.Result):
         return parsed
     script += parsed
 
     if litConfig.noExecute:
         return lit.Test.Result(Test.PASS)
 

llvm/utils/lit/tests/Inputs/lit-opts/lit.cfg

 import lit.formats
 
 config.name = "lit-opts"
 config.suffixes = [".txt"]
 config.test_format = lit.formats.ShTest()
 config.test_source_root = None
 config.test_exec_root = None
-config.substitutions.append(("%var", lit_config.params.get("var", "")))
+config.substitutions.append(("%var", lit_config.params.get("var", "default")))

llvm/utils/lit/tests/Inputs/shtest-define/examples/param-subst.txt

 ; This example originally appeared in TestingGuide.rst except here we've added
 ; echo to the clang/FileCheck command line to be executed.
 
 ; DEFINE: %{cflags} =
 ; DEFINE: %{fcflags} =
 
 ; DEFINE: %{check} =                                                           \
 ; DEFINE:   echo '                                                             \
 ; DEFINE:   %clang_cc1 -verify -fopenmp -fopenmp-version=51 %{cflags}          \
 ; DEFINE:              -emit-llvm -o - %s |                                    \
 ; DEFINE:     FileCheck %{fcflags} %s                                          \
 ; DEFINE:   '
 
 ; REDEFINE: %{cflags} = -triple x86_64-apple-darwin10.6.0 -fopenmp-simd
 ; REDEFINE: %{fcflags} = -check-prefix=SIMD
 ; RUN: %{check}
-; CHECK: %clang_cc1 -verify -fopenmp -fopenmp-version=51 -triple x86_64-apple-darwin10.6.0 -fopenmp-simd -emit-llvm -o - {{.*}} | FileCheck -check-prefix=SIMD {{.*}}
+; CHECK:# | %clang_cc1 -verify -fopenmp -fopenmp-version=51 -triple x86_64-apple-darwin10.6.0 -fopenmp-simd -emit-llvm -o - {{.*}} | FileCheck -check-prefix=SIMD {{.*}}
 
 ; REDEFINE: %{cflags} = -triple x86_64-unknown-linux-gnu -fopenmp-simd
 ; REDEFINE: %{fcflags} = -check-prefix=SIMD
 ; RUN: %{check}
-; CHECK: %clang_cc1 -verify -fopenmp -fopenmp-version=51 -triple x86_64-unknown-linux-gnu -fopenmp-simd -emit-llvm -o - {{.*}} | FileCheck -check-prefix=SIMD {{.*}}
+; CHECK:# | %clang_cc1 -verify -fopenmp -fopenmp-version=51 -triple x86_64-unknown-linux-gnu -fopenmp-simd -emit-llvm -o - {{.*}} | FileCheck -check-prefix=SIMD {{.*}}
 
 ; REDEFINE: %{cflags} = -triple x86_64-apple-darwin10.6.0
 ; REDEFINE: %{fcflags} = -check-prefix=NO-SIMD
 ; RUN: %{check}
-; CHECK: %clang_cc1 -verify -fopenmp -fopenmp-version=51 -triple x86_64-apple-darwin10.6.0 -emit-llvm -o - {{.*}} | FileCheck -check-prefix=NO-SIMD {{.*}}
+; CHECK:# | %clang_cc1 -verify -fopenmp -fopenmp-version=51 -triple x86_64-apple-darwin10.6.0 -emit-llvm -o - {{.*}} | FileCheck -check-prefix=NO-SIMD {{.*}}
 
 ; REDEFINE: %{cflags} = -triple x86_64-unknown-linux-gnu
 ; REDEFINE: %{fcflags} = -check-prefix=NO-SIMD
 ; RUN: %{check}
-; CHECK: %clang_cc1 -verify -fopenmp -fopenmp-version=51 -triple x86_64-unknown-linux-gnu -emit-llvm -o - {{.*}} | FileCheck -check-prefix=NO-SIMD {{.*}}
+; CHECK:# | %clang_cc1 -verify -fopenmp -fopenmp-version=51 -triple x86_64-unknown-linux-gnu -emit-llvm -o - {{.*}} | FileCheck -check-prefix=NO-SIMD {{.*}}
 
 ; CHECK: Passed: 1

llvm/utils/lit/tests/Inputs/shtest-define/expansion-order.txt

 # Redefine the %{global:greeting} parameter of %{global:echo} before using it.
 # The necessary expansion order was established in the test suite config
 # (%{global:echo} before %{global:greeting}), and redefining the parameter
 # doesn't change that expansion order.  That order would be reversed if
 # %{global:greeting} were handled as a new substitution, preventing full
 # expansion.
 #
 # REDEFINE: %{global:greeting}=Hello
 # RUN: %{global:echo}
-# CHECK: GLOBAL: Hello World
+# CHECK:# | GLOBAL: Hello World
 
 # We can redefine the test suite config's substitutions multiple times.  Again,
 # the expansion order remains the same (%{global:echo} before %{global:greeting}
 # before %{global:what}) but would be reversed if these were handled as new
 # substitutions, preventing full expansion.
 #
 # REDEFINE: %{global:greeting}=Goodbye %{global:what}
 # REDEFINE: %{global:what}=Sleep
 # RUN: %{global:echo}
-# CHECK: GLOBAL: Goodbye Sleep Sleep
+# CHECK:# | GLOBAL: Goodbye Sleep Sleep
 
 # A new local substitution is prepended to the substitution list so that it can
 # depend on all substitutions that were defined previously, including those from
 # the test suite config.
 #
 # DEFINE: %{local:greeting}=Hey %{global:what}
 # DEFINE: %{local:echo}=echo "LOCAL: %{local:greeting} %{global:what}"
 # RUN: %{local:echo}
-# CHECK: LOCAL: Hey Sleep Sleep
+# CHECK:# | LOCAL: Hey Sleep Sleep
 
 # As for substitutions from the test suite config, redefining local
 # substitutions should not change the expansion order.  Again, the expansion
 # order would be reversed if these were instead handled as new substitutions,
 # preventing full expansion.
 #
 # REDEFINE: %{local:greeting}=So Long %{global:what}
 # REDEFINE: %{global:what}=World
 # RUN: %{local:echo}
-# CHECK: LOCAL: So Long World World
+# CHECK:# | LOCAL: So Long World World
 
 # CHECK: Passed: 1

llvm/utils/lit/tests/Inputs/shtest-define/line-number-substitutions.txt

 # Does it work as expected directly in RUN lines?
 # RUN: echo %(line), %(line-1), %(line+2)
-# CHECK: [[#@LINE-1]], [[#@LINE-2]], [[#@LINE+1]]
+# CHECK:# | [[#@LINE-1]], [[#@LINE-2]], [[#@LINE+1]]
 
 # %(line) substitutions refer to the original DEFINE/REDEFINE line not the RUN
 # line they eventually appear within.
 #
 # DEFINE: %{lines} = %(line)
 # RUN: echo '%{lines}'
-# CHECK: [[#@LINE-2]]
+# CHECK:# | [[#@LINE-2]]
 #
 # REDEFINE: %{lines} = %(line),                                                \
 # REDEFINE:            %(line),                                                \
 # REDEFINE:            %(line)
 # RUN: echo '%{lines}'
-# CHECK: [[#@LINE-4]], [[#@LINE-3]], [[#@LINE-2]]
+# CHECK:# | [[#@LINE-4]], [[#@LINE-3]], [[#@LINE-2]]
 
 # %(line+N) and %{line-N) should work too.
 #
 # DEFINE: %{lines-rel} = %(line+1),                                            \
 # DEFINE:                %(line),                                              \
 # DEFINE:                %(line-1)
 # RUN: echo '%{lines-rel}'
-# CHECK: [[#@LINE-3]], [[#@LINE-3]], [[#@LINE-3]]
+# CHECK:# | [[#@LINE-3]], [[#@LINE-3]], [[#@LINE-3]]
 #
 # REDEFINE: %{lines-rel} = %(line+5),                                          \
 # REDEFINE:                %(line+0),                                          \
 # REDEFINE:                %(line-10)
 # RUN: echo '%{lines-rel}'
-# CHECK: [[#@LINE+1]], [[#@LINE-3]], [[#@LINE-12]]
+# CHECK:# | [[#@LINE+1]], [[#@LINE-3]], [[#@LINE-12]]
 
 # CHECK: Passed: 1

llvm/utils/lit/tests/Inputs/shtest-define/name-chars.txt

 # DEFINE: %{abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789} = ok
 # RUN: echo '%{abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789}'
-# CHECK: ok
+# CHECK:# | ok
 
 # DEFINE: %{FooBar} = ok at %(line)
 # RUN: echo '%{FooBar}'
-# CHECK: ok at [[#@LINE - 2]]
+# CHECK:# | ok at [[#@LINE - 2]]
 
 # DEFINE: %{fooBar} = ok at %(line)
 # RUN: echo '%{fooBar}'
-# CHECK: ok at [[#@LINE - 2]]
+# CHECK:# | ok at [[#@LINE - 2]]
 
 # DEFINE: %{foo-bar-} = ok at %(line)
 # RUN: echo '%{foo-bar-}'
-# CHECK: ok at [[#@LINE - 2]]
+# CHECK:# | ok at [[#@LINE - 2]]
 
 # DEFINE: %{foo:bar:} = ok at %(line)
 # RUN: echo '%{foo:bar:}'
-# CHECK: ok at [[#@LINE - 2]]
+# CHECK:# | ok at [[#@LINE - 2]]
 
 # DEFINE: %{_foo_bar_} = ok at %(line)
 # RUN: echo '%{_foo_bar_}'
-# CHECK: ok at [[#@LINE - 2]]
+# CHECK:# | ok at [[#@LINE - 2]]
 
 # CHECK: Passed: 1

llvm/utils/lit/tests/Inputs/shtest-define/recursiveExpansionLimit.txt

 # These are defined in the wrong order for non-recursive expansion: %{inner} is
 # defined after it's referenced.
 
 # DEFINE: %{outer}=%{inner}
 # DEFINE: %{inner}=expanded
 
 # RUN: echo '%{outer}'
 
-# CHECK-NON-RECUR:%{inner}
-# CHECK-RECUR:expanded
+# CHECK-NON-RECUR:# | %{inner}
+# CHECK-RECUR:# | expanded
 
 # CHECK: Passed: 1

llvm/utils/lit/tests/Inputs/shtest-define/value-equals.txt

 # After the initial '=', the value can contain '=' with no special meaning.
 
 # DEFINE: %{equals} = FileCheck -check-prefixes=FOO,BAR
 # RUN: echo '%{equals}'
-# CHECK: FileCheck -check-prefixes=FOO,BAR
+# CHECK:# | FileCheck -check-prefixes=FOO,BAR
 #
 # REDEFINE: %{equals} == == =
 # RUN: echo '%{equals}'
-# CHECK: = == =
+# CHECK:# | = == =
 
 # DEFINE: %{continue-equals} = FileCheck -strict-whitespace -match-full-lines \
 # DEFINE:                      -check-prefixes=FOO,BAR
 # RUN: echo '%{continue-equals}'
-# CHECK: FileCheck -strict-whitespace -match-full-lines -check-prefixes=FOO,BAR
+# CHECK:# | FileCheck -strict-whitespace -match-full-lines -check-prefixes=FOO,BAR
 #
 # REDEFINE: %{continue-equals} = FileCheck -input-file=test.txt                \
 # REDEFINE:                      -implicit-check-not=foobar                    \
 # REDEFINE:                      -check-prefixes=FOO,BAR
 # RUN: echo '%{continue-equals}'
-# CHECK: FileCheck -input-file=test.txt -implicit-check-not=foobar -check-prefixes=FOO,BAR
+# CHECK:# | FileCheck -input-file=test.txt -implicit-check-not=foobar -check-prefixes=FOO,BAR
 
 # CHECK: Passed: 1

llvm/utils/lit/tests/Inputs/shtest-define/value-escaped.txt

 # FIXME: The doubled backslashes occur under windows.  That's almost surely a
 # lit issue beyond DEFINE/REDEFINE.
 
 # Escape sequences that can appear in python re.sub replacement strings have no
 # special meaning in the value.
 
 # DEFINE: %{escape} = \g<0>\n
 # RUN: echo '%{escape}'
-# CHECK: {{\\?}}\g<0>{{\\?}}\n
+# CHECK:# | {{\\?}}\g<0>{{\\?}}\n
 
 # REDEFINE: %{escape} = \n                                                     \
 # REDEFINE:             \g<param>
 # RUN: echo '%{escape}'
-# CHECK: {{\\?}}\n {{\\?}}\g<param>
+# CHECK:# | {{\\?}}\n {{\\?}}\g<param>
 
 # CHECK: Passed: 1

llvm/utils/lit/tests/Inputs/shtest-define/ws-and-continuations.txt

 # Empty values are permitted and reasonable, especially when just establishing
 # expansion order.
 #
 # DEFINE: %{empty}=
 # RUN: echo "'%{empty}'"
-# CHECK:''
+# CHECK:# | ''
 #
 # REDEFINE: %{empty}=
 # RUN: echo "'%{empty}'"
-# CHECK:''
+# CHECK:# | ''
 
 # A value consisting only of whitespace is trimmed to the empty string.
 #
 #               v~~ intentional whitespace
 # DEFINE: %{ws}=   
 # RUN: echo "'%{ws}'"
-# CHECK:''
+# CHECK:# | ''
 #
 #                 v intentional whitespace
 # REDEFINE: %{ws}= 
 # RUN: echo "'%{ws}'"
-# CHECK:''
+# CHECK:# | ''
 
 # Whitespace is not required around the name or value.
 #
 # DEFINE:%{no-whitespace}=abc
 # RUN: echo "'%{no-whitespace}'"
-# CHECK:'abc'
+# CHECK:# | 'abc'
 #
 # REDEFINE:%{no-whitespace}=HelloWorld
 # RUN: echo "'%{no-whitespace}'"
-# CHECK:'HelloWorld'
+# CHECK:# | 'HelloWorld'
 
 # Whitespace is not required between substitutions in a value.
 #
 # DEFINE: %{adjacent0} = foo
 # DEFINE: %{adjacent1} = bar
 # DEFINE: %{has-adjacent-substs} = %{adjacent0}%{adjacent1}
 # RUN: echo "'%{has-adjacent-substs}'"
-# CHECK:'foobar'
+# CHECK:# | 'foobar'
 #
 # REDEFINE: %{has-adjacent-substs} = %{adjacent0}%{adjacent1}%{adjacent0}
 # RUN: echo "'%{has-adjacent-substs}'"
-# CHECK:'foobarfoo'
+# CHECK:# | 'foobarfoo'
 
 # Exact whitespace is preserved within the value, but whitespace enclosing the
 # name or value is discarded.  ('%{' and '}' are part of the name, and
 # whitespace in between isn't permitted.)
 #
 #                                       v~~ intentional whitespace
 # DEFINE:   %{whitespace}  =  abc    def   
 # RUN: echo "'%{whitespace}'"
-# CHECK:'abc    def'
+# CHECK:# | 'abc    def'
 #                                      v intentional whitespace
 # REDEFINE: %{whitespace} = Hello World 
 # RUN: echo "'%{whitespace}'"
-# CHECK:'Hello World'
+# CHECK:# | 'Hello World'
 
 # Line continuations in the value are permitted and collapse whitespace.
 #
 # DEFINE: %{continue} = abc\
 # DEFINE:def \
 # DEFINE:ghi\
 # DEFINE: jkl \
 # DEFINE: mno  \
 # DEFINE:  pqr 
 #             ^ intentional whitespace
 # RUN: echo "'%{continue}'"
-# CHECK:'abc def ghi jkl mno pqr'
+# CHECK:# | 'abc def ghi jkl mno pqr'
 #
 # REDEFINE: %{continue} =  abc  \
 # REDEFINE: def
 # RUN: echo "'%{continue}'"
-# CHECK:'abc def'
+# CHECK:# | 'abc def'
 
 # Whitespace at the end of the line after a '\' is ignored, and it's treated as
 # a line continuation.  Otherwise, the behavior would be hard to understand
 # because it looks like a line continuation.
 #
 #                                   v~~~~~~~~~~~ intentional whitespace
 # DEFINE: %{ws-after-continue}=foo \            
 # DEFINE: bar                      \ 
 #                                   ^ intentional whitespace
 # DEFINE: baz
 # RUN: echo "'%{ws-after-continue}'"
-# CHECK:'foo bar baz'
+# CHECK:# | 'foo bar baz'
 #
 #                                     v intentional whitespace
 # REDEFINE: %{ws-after-continue}=foo \ 
 # REDEFINE: bar                      \            
 #                                     ^~~~~~~~~~~~ intentional whitespace
 # REDEFINE: baz
 # RUN: echo "'%{ws-after-continue}'"
-# CHECK:'foo bar baz'
+# CHECK:# | 'foo bar baz'
 
 # A line continuation is recognized anywhere.  It should be used only where
 # whitespace is permitted because it reduces to a single space.
 #
 # Directives with at least one non-whitespace character (could be '\') are
 # permitted even if they contribute nothing to the value.  There might be no
 # practical use, but check that it behaves as expected.
 #
 # DEFINE:\
 # DEFINE:%{blank-lines}\
 # DEFINE:\
 # DEFINE:=\
 # DEFINE:\
 # DEFINE:a
 # RUN: echo "'%{blank-lines}'"
-# CHECK:'a'
+# CHECK:# | 'a'
 #
 # REDEFINE:                  \
 # REDEFINE: %{blank-lines}   \
 # REDEFINE:                  \
 # REDEFINE:                = \
 # REDEFINE:                  \
 # REDEFINE:      a           \
 # REDEFINE:                  \
 # REDEFINE:      b           \
 # REDEFINE:                  \
 # REDEFINE:      c
 # RUN: echo "'%{blank-lines}'"
-# CHECK:'a b c'
+# CHECK:# | 'a b c'
 
 # The fourth DEFINE line is deceptive because it looks like a new substitution,
 # but it's actually a continuation of the previous value.
 #
 # DEFINE: %{name}=x
 # DEFINE: %{value}=3
 # DEFINE: %{deceptive-continue}=echo \
 # DEFINE: %{name}=%{value}
 # RUN: %{deceptive-continue}
-# CHECK:x=3
+# CHECK:# | x=3
 
 # CHECK:{{ *}}Passed: 1

llvm/utils/lit/tests/Inputs/shtest-if-else/test.txt

-#       CHECK: -- Testing:{{.*}}
-#  CHECK-NEXT: PASS: shtest-if-else :: test.txt (1 of 1)
-#  CHECK-NEXT: Exit Code: 0
-# CHECK-EMPTY:
-#  CHECK-NEXT: Command Output (stdout):
-#  CHECK-NEXT: --
+# CHECK: -- Testing:{{.*}}
+# CHECK-NEXT: PASS: shtest-if-else :: test.txt (1 of 1)
+#      CHECK: Command Output (stdout):
+# CHECK-NEXT: --
 
 # RUN: %if feature %{ echo "test-1" %}
-#  CHECK-NEXT: {{^.*"RUN}}: at line [[#@LINE-1]]"
-#       CHECK: # command output:
-#  CHECK-NEXT: test-1
-# CHECK-EMPTY:
+#      CHECK: # {{RUN}}: at line [[#@LINE-1]]
+# CHECK-NEXT: echo "test-1"
 
 # If %else is not present it is treated like %else %{%}. Empty commands
 # are ignored.
 #
 # RUN: %if nofeature %{ echo "fail" %}
-#  CHECK-NEXT: {{^.*"RUN}}: at line [[#@LINE-1]]"
-#   CHECK-NOT: fail
+#     CHECK: # {{RUN}}: at line [[#@LINE-1]] has no command after substitutions
+# CHECK-NOT: fail
 
 # RUN: %if nofeature %{ echo "fail" %} %else %{ echo "test-2" %}
-#  CHECK-NEXT: {{^.*"RUN}}: at line [[#@LINE-1]]"
-#       CHECK: # command output:
-#  CHECK-NEXT: test-2
-# CHECK-EMPTY:
+#      CHECK: # {{RUN}}: at line [[#@LINE-1]]
+# CHECK-NEXT: echo "test-2"
 
 # Spaces inside curly braces are not ignored
 #
 # RUN: echo test-%if feature %{ 3 %} %else %{ fail %}-test
 # RUN: echo test-%if feature %{ 4 4 %} %else %{ fail %}-test
 # RUN: echo test-%if nofeature %{ fail %} %else %{ 5 5 %}-test
-#  CHECK-NEXT: {{^.*"RUN}}: at line [[#@LINE-3]]"
-#       CHECK: # command output:
-#  CHECK-NEXT: test- 3 -test
-# CHECK-EMPTY:
-#  CHECK-NEXT: {{^.*"RUN}}: at line [[#@LINE-6]]"
-#       CHECK: # command output:
-#  CHECK-NEXT: test- 4 4 -test
-# CHECK-EMPTY:
-#  CHECK-NEXT: {{^.*"RUN}}: at line [[#@LINE-9]]"
-#       CHECK: # command output:
-#  CHECK-NEXT: test- 5 5 -test
-# CHECK-EMPTY:
+#      CHECK: # {{RUN}}: at line [[#@LINE-3]]
+# CHECK-NEXT: echo test- 3 -test
+#      CHECK: # {{RUN}}: at line [[#@LINE-4]]
+# CHECK-NEXT: echo test- 4 4 -test
+#      CHECK: # {{RUN}}: at line [[#@LINE-5]]
+# CHECK-NEXT: echo test- 5 5 -test
 
 # Escape line breaks for multi-line expressions
 #
 # RUN: %if feature  \
 # RUN:   %{ echo     \
 # RUN:     "test-5" \
 # RUN:   %}
-#  CHECK-NEXT: {{^.*"RUN}}: at line [[#@LINE-4]]"
-#       CHECK: # command output:
-#  CHECK-NEXT: test-5
-# CHECK-EMPTY:
+#      CHECK: # {{RUN}}: at line [[#@LINE-4]]
+# CHECK-NEXT: echo "test-5"
 
 # RUN: %if nofeature       \
 # RUN:   %{ echo "fail" %}   \
 # RUN: %else               \
 # RUN:   %{ echo "test-6" %}
-#  CHECK-NEXT: {{^.*"RUN}}: at line [[#@LINE-4]]"
-#       CHECK: # command output:
-#  CHECK-NEXT: test-6
-# CHECK-EMPTY:
+#      CHECK: # {{RUN}}: at line [[#@LINE-4]]
+# CHECK-NEXT: echo "test-6"
 
 # RUN: echo "test%if feature %{%} %else %{%}-7"
-#  CHECK-NEXT: {{^.*"RUN}}: at line [[#@LINE-1]]"
-#       CHECK: # command output:
-#  CHECK-NEXT: test-7
-# CHECK-EMPTY:
+#      CHECK: # {{RUN}}: at line [[#@LINE-1]]
+# CHECK-NEXT: echo "test-7"
 
 # Escape %if. Without %if..%else context '%{' and '%}' are treated
 # literally.
 #
 # RUN: echo %%if feature %{ echo "test-8" %}
-#  CHECK-NEXT: {{^.*"RUN}}: at line [[#@LINE-1]]"
-#       CHECK: # command output:
-#  CHECK-NEXT: %if feature %{ echo test-8 %}
-# CHECK-EMPTY:
+#      CHECK: # {{RUN}}: at line [[#@LINE-1]]
+# CHECK-NEXT: echo %if feature %{ echo "test-8" %}
 
 # Nested expressions are supported:
 #
 # RUN: echo %if feature %{ %if feature %{ %if nofeature %{"fail"%} %else %{"test-9"%} %} %}
-#  CHECK-NEXT: {{^.*"RUN}}: at line [[#@LINE-1]]"
-#       CHECK: # command output:
-#  CHECK-NEXT: test-9
-# CHECK-EMPTY:
+#      CHECK: # {{RUN}}: at line [[#@LINE-1]]
+# CHECK-NEXT: echo "test-9"
 
 # Binary expression evaluation and regex match can be used as
 # conditions.
 #
 # RUN: echo %if feature && !nofeature %{ "test-10" %}
 # RUN: echo %if feature && nofeature %{ "fail" %} %else %{ "test-11" %}
 # RUN: echo %if {{fea.+}} %{ "test-12" %} %else %{ "fail" %}
-#  CHECK-NEXT: {{^.*"RUN}}: at line [[#@LINE-3]]"
-#       CHECK: # command output:
-#  CHECK-NEXT: test-10
-# CHECK-EMPTY:
-#  CHECK-NEXT: {{^.*"RUN}}: at line [[#@LINE-6]]"
-#       CHECK: # command output:
-#  CHECK-NEXT: test-11
-# CHECK-EMPTY:
-#  CHECK-NEXT: {{^.*"RUN}}: at line [[#@LINE-9]]"
-#       CHECK: # command output:
-#  CHECK-NEXT: test-12
-# CHECK-EMPTY:
+#      CHECK: # {{RUN}}: at line [[#@LINE-3]]
+# CHECK-NEXT: echo "test-10"
+#      CHECK: # {{RUN}}: at line [[#@LINE-4]]
+# CHECK-NEXT: echo "test-11"
+#      CHECK: # {{RUN}}: at line [[#@LINE-5]]
+# CHECK-NEXT: echo "test-12"
 
 # Spaces between %if and %else are ignored. If there is no %else -
 # space after %if %{...%} is not ignored.
 #
 # RUN: echo XX %if feature %{YY%} ZZ
 # RUN: echo AA %if feature %{BB%} %else %{CC%} DD
 # RUN: echo AA %if nofeature %{BB%} %else %{CC%} DD
-#  CHECK-NEXT: {{^.*"RUN}}: at line [[#@LINE-3]]"
-#       CHECK: # command output:
-#  CHECK-NEXT: XX YY ZZ
-# CHECK-EMPTY:
-#  CHECK-NEXT: {{^.*"RUN}}: at line [[#@LINE-6]]"
-#       CHECK: # command output:
-#  CHECK-NEXT: AA BB DD
-# CHECK-EMPTY:
-#  CHECK-NEXT: {{^.*"RUN}}: at line [[#@LINE-9]]"
-#       CHECK: # command output:
-#  CHECK-NEXT: AA CC DD
-# CHECK-EMPTY:
+#      CHECK: # {{RUN}}: at line [[#@LINE-3]]
+# CHECK-NEXT: echo XX YY ZZ
+#      CHECK: # {{RUN}}: at line [[#@LINE-4]]
+# CHECK-NEXT: echo AA BB DD
+#      CHECK: # {{RUN}}: at line [[#@LINE-5]]
+# CHECK-NEXT: echo AA CC DD
 
 # '{' and '}' can be used without escaping
 #
 # RUN: %if feature %{echo {}%}
-#  CHECK-NEXT: {{^.*"RUN}}: at line [[#@LINE-1]]"
-#       CHECK: # command output:
-#  CHECK-NEXT: {}
-# CHECK-EMPTY:
+#      CHECK: # {{RUN}}: at line [[#@LINE-1]]
+# CHECK-NEXT: echo {}
 
 # Spaces are not required
 #
 # RUN: echo %if feature%{"ok"%}%else%{"fail"%}
-#  CHECK-NEXT: {{^.*"RUN}}: at line [[#@LINE-1]]"
-#       CHECK: # command output:
-#  CHECK-NEXT: ok
-# CHECK-EMPTY:
+#      CHECK: # {{RUN}}: at line [[#@LINE-1]]
+# CHECK-NEXT: echo "ok"
 
 # Substitutions with braces are handled correctly
 #
 # RUN: echo %{sub} %if feature%{test-%{sub}%}%else%{"fail"%}
-#  CHECK-NEXT: {{^.*"RUN}}: at line [[#@LINE-1]]"
-#       CHECK: # command output:
-#  CHECK-NEXT: ok test-ok
-# CHECK-EMPTY:
+#      CHECK: # {{RUN}}: at line [[#@LINE-1]]
+# CHECK-NEXT: echo ok test-ok

llvm/utils/lit/tests/Inputs/shtest-output-printing/basic.txt

 # RUN: true
 # RUN: echo hi
-# RUN: not not wc missing-file &> %t.out
+# RUN: not not wc missing-file &> %t.out || true
+# RUN: not %{python} %S/write-a-lot.py &> %t.out

llvm/utils/lit/tests/Inputs/shtest-output-printing/lit.cfg

 import lit.formats
 
 config.name = "shtest-output-printing"
 config.suffixes = [".txt"]
+config.substitutions.append(("%{python}", f'"{sys.executable}"'))
 config.test_format = lit.formats.ShTest(execute_external=False)

llvm/utils/lit/tests/Inputs/shtest-output-printing/write-a-lot.py

+#!/usr/bin/env python
+
+import sys
+
+sys.stdout.write("All work and no play makes Jack a dull boy.\n" * 1000)
+sys.stdout.flush()

llvm/utils/lit/tests/Inputs/shtest-shell/echo-at-redirect-stderr.txt

+RUN: @echo 2> %t

llvm/utils/lit/tests/Inputs/shtest-shell/echo-at-redirect-stdin.txt

+RUN: touch %t
+RUN: @echo < %t

llvm/utils/lit/tests/Inputs/shtest-shell/echo-redirect-stderr.txt

+RUN: echo 2> %t

llvm/utils/lit/tests/Inputs/shtest-shell/echo-redirect-stdin.txt

+RUN: touch %t
+RUN: echo < %t

llvm/utils/lit/tests/allow-retries.py

 # Test that a per-file ALLOW_RETRIES overwrites the config-wide test_retry_attempts property, if any.
 #
 # RUN: rm -f %t.counter
 # RUN: %{lit} %{inputs}/allow-retries/succeeds-within-limit.py -Dtest_retry_attempts=2 -Dcounter=%t.counter -Dpython=%{python} | FileCheck --check-prefix=CHECK-TEST2 %s
 # CHECK-TEST2: Passed With Retry: 1
 
 # This test does not succeed within the allowed retry limit
 #
-# RUN: not %{lit} %{inputs}/allow-retries/does-not-succeed-within-limit.py | FileCheck --check-prefix=CHECK-TEST3 %s
-# CHECK-TEST3: Failed Tests (1):
-# CHECK-TEST3: allow-retries :: does-not-succeed-within-limit.py
+# Check that the execution trace isn't corrupt due to reprocessing the script
+# multiple times (e.g., '%dbg(...)' processing used to accumulate across
+# retries).
+#
+# RUN: not %{lit} %{inputs}/allow-retries/does-not-succeed-within-limit.py -v |\
+# RUN:   FileCheck --check-prefix=CHECK-TEST3 -match-full-lines %s
+#
+#       CHECK-TEST3: FAIL: allow-retries :: does-not-succeed-within-limit.py (1 of 1)
+#  CHECK-TEST3-NEXT: {{\**}} TEST 'allow-retries :: does-not-succeed-within-limit.py' FAILED {{\**}}
+#  CHECK-TEST3-NEXT: Exit Code: 1
+# CHECK-TEST3-EMPTY:
+#  CHECK-TEST3-NEXT: Command Output (stdout):
+#  CHECK-TEST3-NEXT: --
+#  CHECK-TEST3-NEXT: # {{RUN}}: at line 3
+#  CHECK-TEST3-NEXT: false
+#  CHECK-TEST3-NEXT: # executed command: false
+#  CHECK-TEST3-NEXT: # note: command had no output on stdout or stderr
+#  CHECK-TEST3-NEXT: # error: command failed with exit status: 1
+# CHECK-TEST3-EMPTY:
+#  CHECK-TEST3-NEXT: --
+#       CHECK-TEST3: Failed Tests (1):
+#       CHECK-TEST3: allow-retries :: does-not-succeed-within-limit.py
 
 # This test should be UNRESOLVED since it has more than one ALLOW_RETRIES
 # lines, and that is not allowed.
 #
 # RUN: not %{lit} %{inputs}/allow-retries/more-than-one-allow-retries-lines.py | FileCheck --check-prefix=CHECK-TEST4 %s
 # CHECK-TEST4: Unresolved Tests (1):
 # CHECK-TEST4: allow-retries :: more-than-one-allow-retries-lines.py
 

 # This test checks that --per-test-coverage doesn't accumulate inserted
 # LLVM_PROFILE_FILE= commands across retries.
 #
 # RUN: rm -f %t.counter
 # RUN: %{lit} -a %{inputs}/test_retry_attempts/test.py --per-test-coverage\
 # RUN:     -Dcounter=%t.counter -Dpython=%{python} | \
 # RUN:   FileCheck --check-prefix=CHECK-TEST7 %s
 #     CHECK-TEST7: Command Output (stdout):
-#     CHECK-TEST7: LLVM_PROFILE_FILE=
-# CHECK-TEST7-NOT: LLVM_PROFILE_FILE=
+#     CHECK-TEST7: # executed command: export LLVM_PROFILE_FILE=
+# CHECK-TEST7-NOT: # executed command: export LLVM_PROFILE_FILE=
 #     CHECK-TEST7: Passed With Retry: 1

llvm/utils/lit/tests/lit-opts.py

 # Check cases where LIT_OPTS has no effect.
 #
 # RUN:                 %{lit} -s %{inputs}/lit-opts | FileCheck %s
 # RUN: env LIT_OPTS=   %{lit} -s %{inputs}/lit-opts | FileCheck %s
 # RUN: env LIT_OPTS=-s %{lit} -s %{inputs}/lit-opts | FileCheck %s
 
 # Check that LIT_OPTS can override command-line options.
 #
 # RUN: env LIT_OPTS=-a \
 # RUN: %{lit} -s %{inputs}/lit-opts \
-# RUN: | FileCheck -check-prefix=SHOW-ALL -DVAR= %s
+# RUN: | FileCheck -check-prefix=SHOW-ALL -DVAR=default %s
 
 # Check that LIT_OPTS understands multiple options with arbitrary spacing.
 #
 # RUN: env LIT_OPTS='-a -v  -Dvar=foobar' \
 # RUN: %{lit} -s %{inputs}/lit-opts \
 # RUN: | FileCheck -check-prefix=SHOW-ALL -DVAR=foobar %s
 
 # Check that LIT_OPTS parses shell-like quotes and escapes.
 #
 # RUN: env LIT_OPTS='-a   -v -Dvar="foo bar"\ baz' \
 # RUN: %{lit} -s %{inputs}/lit-opts \
 # RUN: | FileCheck -check-prefix=SHOW-ALL -DVAR="foo bar baz" %s
 
 # CHECK:      Testing: 1 tests
 # CHECK-NOT:  PASS
 # CHECK:      Passed: 1
 
 # SHOW-ALL:     Testing: 1 tests
 # SHOW-ALL:     PASS: lit-opts :: test.txt (1 of 1)
-# SHOW-ALL:     {{^}}[[VAR]]
+# SHOW-ALL:     echo [[VAR]]
 # SHOW-ALL-NOT: PASS
 # SHOW-ALL:     Passed: 1

llvm/utils/lit/tests/shtest-define.py

 # REDEFINE: %{fc-args} =
 
 # Check that per-test changes to substitutions don't affect other tests in the
 # same LIT invocation.
 #
 # RUN: %{lit} -va %{my-inputs}/shared-substs-*.txt 2>&1 |                      \
 # RUN:   FileCheck -check-prefix=SHARED-SUBSTS -match-full-lines %s
 #
-# SHARED-SUBSTS: shared-substs-0.txt
-# SHARED-SUBSTS: GLOBAL: World
-# SHARED-SUBSTS: LOCAL0: LOCAL0:Hello LOCAL0:World
-# SHARED-SUBSTS: LOCAL0: subst
-#
-# SHARED-SUBSTS: shared-substs-1.txt
-# SHARED-SUBSTS: GLOBAL: World
-# SHARED-SUBSTS: LOCAL1: LOCAL1:Hello LOCAL1:World
-# SHARED-SUBSTS: LOCAL1: subst
+# SHARED-SUBSTS:# | shared-substs-0.txt
+# SHARED-SUBSTS:# | GLOBAL: World
+# SHARED-SUBSTS:# | LOCAL0: LOCAL0:Hello LOCAL0:World
+# SHARED-SUBSTS:# | LOCAL0: subst
+#
+# SHARED-SUBSTS:# | shared-substs-1.txt
+# SHARED-SUBSTS:# | GLOBAL: World
+# SHARED-SUBSTS:# | LOCAL1: LOCAL1:Hello LOCAL1:World
+# SHARED-SUBSTS:# | LOCAL1: subst
 #
 # REDEFINE: %{test} = shared-substs-0.txt
 # RUN: %{record-test}
 # REDEFINE: %{test} = shared-substs-1.txt
 # RUN: %{record-test}
 
 # REDEFINE: %{test} = value-equals.txt
 # RUN: %{run-and-record-test}

llvm/utils/lit/tests/shtest-env.py

 # Check the env command
 
 # RUN: not %{lit} -a -v %{inputs}/shtest-env \
 # RUN: | FileCheck -match-full-lines %s
 #
 # END.
 
 # Make sure env commands are included in printed commands.
 
 # CHECK: -- Testing: 16 tests{{.*}}
 
 # CHECK: FAIL: shtest-env :: env-args-last-is-assign.txt ({{[^)]*}})
-# CHECK: $ "env" "FOO=1"
-# CHECK: Error: 'env' requires a subcommand
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: env FOO=1
+# CHECK: # executed command: env FOO=1
+# CHECK: # | Error: 'env' requires a subcommand
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: FAIL: shtest-env :: env-args-last-is-u-arg.txt ({{[^)]*}})
-# CHECK: $ "env" "-u" "FOO"
-# CHECK: Error: 'env' requires a subcommand
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: env -u FOO
+# CHECK: # executed command: env -u FOO
+# CHECK: # | Error: 'env' requires a subcommand
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: FAIL: shtest-env :: env-args-last-is-u.txt ({{[^)]*}})
-# CHECK: $ "env" "-u"
-# CHECK: Error: 'env' requires a subcommand
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: env -u
+# CHECK: # executed command: env -u
+# CHECK: # | Error: 'env' requires a subcommand
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: FAIL: shtest-env :: env-args-nested-none.txt ({{[^)]*}})
-# CHECK: $ "env" "env" "env"
-# CHECK: Error: 'env' requires a subcommand
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: env env env
+# CHECK: # executed command: env env env
+# CHECK: # | Error: 'env' requires a subcommand
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: FAIL: shtest-env :: env-args-none.txt ({{[^)]*}})
-# CHECK: $ "env"
-# CHECK: Error: 'env' requires a subcommand
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: env
+# CHECK: # executed command: env
+# CHECK: # | Error: 'env' requires a subcommand
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: FAIL: shtest-env :: env-calls-cd.txt ({{[^)]*}})
-# CHECK: $ "env" "-u" "FOO" "BAR=3" "cd" "foobar"
-# CHECK: Error: 'env' cannot call 'cd'
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: env -u FOO BAR=3 cd foobar
+# CHECK: # executed command: env -u FOO BAR=3 cd foobar
+# CHECK: # | Error: 'env' cannot call 'cd'
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: FAIL: shtest-env :: env-calls-colon.txt ({{[^)]*}})
-# CHECK: $ "env" "-u" "FOO" "BAR=3" ":"
-# CHECK: Error: 'env' cannot call ':'
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: env -u FOO BAR=3 :
+# CHECK: # executed command: env -u FOO BAR=3 :
+# CHECK: # | Error: 'env' cannot call ':'
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: FAIL: shtest-env :: env-calls-echo.txt ({{[^)]*}})
-# CHECK: $ "env" "-u" "FOO" "BAR=3" "echo" "hello" "world"
-# CHECK: Error: 'env' cannot call 'echo'
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: env -u FOO BAR=3 echo hello world
+# CHECK: # executed command: env -u FOO BAR=3 echo hello world
+# CHECK: # | Error: 'env' cannot call 'echo'
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: PASS: shtest-env :: env-calls-env.txt ({{[^)]*}})
-# CHECK: $ "env" "env" "{{[^"]*}}" "print_environment.py"
-# CHECK: $ "env" "FOO=2" "env" "BAR=1" "{{[^"]*}}" "print_environment.py"
-# CHECK: $ "env" "-u" "FOO" "env" "-u" "BAR" "{{[^"]*}}" "print_environment.py"
-# CHECK: $ "env" "-u" "FOO" "BAR=1" "env" "-u" "BAR" "FOO=2" "{{[^"]*}}" "print_environment.py"
-# CHECK: $ "env" "-u" "FOO" "BAR=1" "env" "-u" "BAR" "FOO=2" "env" "BAZ=3" "{{[^"]*}}" "print_environment.py"
-# CHECK-NOT: ${{.*}}print_environment.py
+# CHECK: env env [[PYTHON:.+]] print_environment.py | {{.*}}
+# CHECK: # executed command: env env [[PYTHON_BARE:.+]] print_environment.py
+# CHECK: env FOO=2 env BAR=1 [[PYTHON]] print_environment.py | {{.*}}
+# CHECK: # executed command: env FOO=2 env BAR=1 [[PYTHON_BARE]] print_environment.py
+# CHECK: env -u FOO env -u BAR [[PYTHON]] print_environment.py | {{.*}}
+# CHECK: # executed command: env -u FOO env -u BAR [[PYTHON_BARE]] print_environment.py
+# CHECK: env -u FOO BAR=1 env -u BAR FOO=2 [[PYTHON]] print_environment.py | {{.*}}
+# CHECK: # executed command: env -u FOO BAR=1 env -u BAR FOO=2 [[PYTHON_BARE]] print_environment.py
+# CHECK: env -u FOO BAR=1 env -u BAR FOO=2 env BAZ=3 [[PYTHON]] print_environment.py | {{.*}}
+# CHECK: # executed command: env -u FOO BAR=1 env -u BAR FOO=2 env BAZ=3 [[PYTHON_BARE]] print_environment.py
+# CHECK-NOT: {{^[^#]}}
+# CHECK: --
 
 # CHECK: FAIL: shtest-env :: env-calls-export.txt ({{[^)]*}})
-# CHECK: $ "env" "-u" "FOO" "BAR=3" "export" "BAZ=3"
-# CHECK: Error: 'env' cannot call 'export'
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: env -u FOO BAR=3 export BAZ=3
+# CHECK: # executed command: env -u FOO BAR=3 export BAZ=3
+# CHECK: # | Error: 'env' cannot call 'export'
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: FAIL: shtest-env :: env-calls-mkdir.txt ({{[^)]*}})
-# CHECK: $ "env" "-u" "FOO" "BAR=3" "mkdir" "foobar"
-# CHECK: Error: 'env' cannot call 'mkdir'
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: env -u FOO BAR=3 mkdir foobar
+# CHECK: # executed command: env -u FOO BAR=3 mkdir foobar
+# CHECK: # | Error: 'env' cannot call 'mkdir'
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: FAIL: shtest-env :: env-calls-not-builtin.txt ({{[^)]*}})
-# CHECK: $ "env" "-u" "FOO" "BAR=3" "not" "rm" "{{.*}}.no-such-file"
-# CHECK: Error: 'env' cannot call 'rm'
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: env -u FOO BAR=3 not rm {{.+}}.no-such-file
+# CHECK: # executed command: env -u FOO BAR=3 not rm {{.+}}.no-such-file{{.*}}
+# CHECK: # | Error: 'env' cannot call 'rm'
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: FAIL: shtest-env :: env-calls-rm.txt ({{[^)]*}})
-# CHECK: $ "env" "-u" "FOO" "BAR=3" "rm" "foobar"
-# CHECK: Error: 'env' cannot call 'rm'
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: env -u FOO BAR=3 rm foobar
+# CHECK: # executed command: env -u FOO BAR=3 rm foobar
+# CHECK: # | Error: 'env' cannot call 'rm'
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: PASS: shtest-env :: env-u.txt ({{[^)]*}})
-# CHECK: $ "{{[^"]*}}" "print_environment.py"
-# CHECK: $ "env" "-u" "FOO" "{{[^"]*}}" "print_environment.py"
-# CHECK: $ "env" "-u" "FOO" "-u" "BAR" "{{[^"]*}}" "print_environment.py"
-# CHECK-NOT: ${{.*}}print_environment.py
+# CHECK: [[PYTHON]] print_environment.py | {{.*}}
+# CHECK: env -u FOO [[PYTHON]] print_environment.py | {{.*}}
+# CHECK: # executed command: env -u FOO [[PYTHON_BARE]] print_environment.py
+# CHECK: env -u FOO -u BAR [[PYTHON]] print_environment.py | {{.*}}
+# CHECK: # executed command: env -u FOO -u BAR [[PYTHON_BARE]] print_environment.py
+# CHECK-NOT: {{^[^#]}}
+# CHECK: --
 
 # CHECK: PASS: shtest-env :: env.txt ({{[^)]*}})
-# CHECK: $ "env" "A_FOO=999" "{{[^"]*}}" "print_environment.py"
-# CHECK: $ "env" "A_FOO=1" "B_BAR=2" "C_OOF=3" "{{[^"]*}}" "print_environment.py"
-# CHECK-NOT: ${{.*}}print_environment.py
+# CHECK: env A_FOO=999 [[PYTHON]] print_environment.py | {{.*}}
+# CHECK: # executed command: env A_FOO=999 [[PYTHON_BARE]] print_environment.py
+# CHECK: env A_FOO=1 B_BAR=2 C_OOF=3 [[PYTHON]] print_environment.py | {{.*}}
+# CHECK: # executed command: env A_FOO=1 B_BAR=2 C_OOF=3 [[PYTHON_BARE]] print_environment.py
+# CHECK-NOT: {{^[^#]}}
+# CHECK: --
 
 # CHECK: PASS: shtest-env :: mixed.txt ({{[^)]*}})
-# CHECK: $ "env" "A_FOO=999" "-u" "FOO" "{{[^"]*}}" "print_environment.py"
-# CHECK: $ "env" "A_FOO=1" "-u" "FOO" "B_BAR=2" "-u" "BAR" "C_OOF=3" "{{[^"]*}}" "print_environment.py"
-# CHECK-NOT: ${{.*}}print_environment.py
+# CHECK: env A_FOO=999 -u FOO [[PYTHON]] print_environment.py | {{.*}}
+# CHECK: # executed command: env A_FOO=999 -u FOO [[PYTHON_BARE]] print_environment.py
+# CHECK: env A_FOO=1 -u FOO B_BAR=2 -u BAR C_OOF=3 [[PYTHON]] print_environment.py | {{.*}}
+# CHECK: # executed command: env A_FOO=1 -u FOO B_BAR=2 -u BAR C_OOF=3 [[PYTHON_BARE]] print_environment.py
+# CHECK-NOT: {{^[^#]}}
+# CHECK: --
 
 # CHECK: Passed:  4
 # CHECK: Failed: 12
 # CHECK-NOT: {{.}}

llvm/utils/lit/tests/shtest-format.py

 # CHECK: PASS: shtest-format :: external_shell/pass.txt
 
 #       CHECK: FAIL: shtest-format :: fail.txt
 #  CHECK-NEXT: *** TEST 'shtest-format :: fail.txt' FAILED ***
 #  CHECK-NEXT: Exit Code: 1
 # CHECK-EMPTY:
 #  CHECK-NEXT: Command Output (stdout):
 #  CHECK-NEXT: --
-#  CHECK-NEXT: $ ":" "RUN: at line 1"
-#  CHECK-NEXT: $ "printf"
-#  CHECK-NEXT: # command output:
-#  CHECK-NEXT: line 1: failed test output on stdout
-#  CHECK-NEXT: line 2: failed test output on stdout
-#  CHECK-NEXT: $ ":" "RUN: at line 2"
-#  CHECK-NEXT: $ "false"
+#  CHECK-NEXT: # RUN: at line 1
+#  CHECK-NEXT: printf "line 1: failed test output on stdout\nline 2: failed test output on stdout"
+#  CHECK-NEXT: executed command: printf 'line 1: failed test output on stdout\nline 2: failed test output on stdout'
+#  CHECK-NEXT: # .---command stdout------------
+#  CHECK-NEXT: # | line 1: failed test output on stdout
+#  CHECK-NEXT: # | line 2: failed test output on stdout
+#  CHECK-NEXT: # `-----------------------------
+#  CHECK-NEXT: # RUN: at line 2
+#  CHECK-NEXT: false
+#  CHECK-NEXT: # executed command: false
+#  CHECK-NEXT: # note: command had no output on stdout or stderr
+#  CHECK-NEXT: # error: command failed with exit status: 1
+# CHECK-EMPTY:
+#  CHECK-NEXT: --
+
 
 # CHECK: UNRESOLVED: shtest-format :: no-test-line.txt
 # CHECK: PASS: shtest-format :: pass.txt
 # CHECK: UNSUPPORTED: shtest-format :: requires-missing.txt
 # CHECK: PASS: shtest-format :: requires-present.txt
 # CHECK: UNRESOLVED: shtest-format :: requires-star.txt
 # CHECK: PASS: shtest-format :: requires-triple.txt
 # CHECK: PASS: shtest-format :: unsupported-expr-false.txt
 # CHECK: UNSUPPORTED: shtest-format :: unsupported-expr-true.txt
 # CHECK: UNRESOLVED: shtest-format :: unsupported-star.txt
 # CHECK: UNSUPPORTED: shtest-format :: unsupported_dir/some-test.txt
 # CHECK: PASS: shtest-format :: xfail-expr-false.txt
 # CHECK: XFAIL: shtest-format :: xfail-expr-true.txt
 # CHECK: XFAIL: shtest-format :: xfail-feature.txt
 # CHECK: XFAIL: shtest-format :: xfail-target.txt
 # CHECK: XFAIL: shtest-format :: xfail.txt
 
 #       CHECK: XPASS: shtest-format :: xpass.txt
 #  CHECK-NEXT: *** TEST 'shtest-format :: xpass.txt' FAILED ***
 #  CHECK-NEXT: Exit Code: 0
 # CHECK-EMPTY:
 #  CHECK-NEXT: Command Output (stdout):
 #  CHECK-NEXT: --
-#  CHECK-NEXT: $ ":" "RUN: at line 1"
-#  CHECK-NEXT: $ "true"
+#  CHECK-NEXT: # RUN: at line 1
+#  CHECK-NEXT: true
+#  CHECK-NEXT: # executed command: true
+# CHECK-EMPTY:
+#  CHECK-NEXT: --
 
 # CHECK: Failed Tests (4)
 # CHECK: shtest-format :: external_shell/fail.txt
 # CHECK: shtest-format :: external_shell/fail_with_bad_encoding.txt
 # CHECK: shtest-format :: external_shell/fail_with_control_chars.txt
 # CHECK: shtest-format :: fail.txt
 
 # CHECK: Unexpectedly Passed Tests (1)

llvm/utils/lit/tests/shtest-if-else.py

 # RUN: %{lit} -v --show-all %{inputs}/shtest-if-else/test.txt \
-# RUN:    | FileCheck %{inputs}/shtest-if-else/test.txt --match-full-lines
+# RUN:    | FileCheck %{inputs}/shtest-if-else/test.txt --match-full-lines \
+# RUN:                --implicit-check-not='RUN:'
 
 # RUN: not %{lit} -v --show-all %{inputs}/shtest-if-else/test-neg1.txt 2>&1 \
 # RUN:    | FileCheck %{inputs}/shtest-if-else/test-neg1.txt
 
 # RUN: not %{lit} -v --show-all %{inputs}/shtest-if-else/test-neg2.txt 2>&1 \
 # RUN:    | FileCheck %{inputs}/shtest-if-else/test-neg2.txt
 
 # RUN: not %{lit} -v --show-all %{inputs}/shtest-if-else/test-neg3.txt 2>&1 \
 # RUN:    | FileCheck %{inputs}/shtest-if-else/test-neg3.txt
 
 # RUN: not %{lit} -v --show-all %{inputs}/shtest-if-else/test-neg4.txt 2>&1 \
 # RUN:    | FileCheck %{inputs}/shtest-if-else/test-neg4.txt

llvm/utils/lit/tests/shtest-inject.py

-# Check that we can inject commands at the beginning of a ShTest.
+# Check that we can inject preamble commands at the beginning of a ShTest.
+#
+# For one case, check the execution trace as these preamble commands have
+# "preamble command" instead of the usual "{{RUN}}: at line N".
 
 # RUN: %{lit} %{inputs}/shtest-inject/test-empty.txt --show-all | FileCheck --check-prefix=CHECK-TEST1 %s
 #
-# CHECK-TEST1: THIS WAS
-# CHECK-TEST1: INJECTED
+#       CHECK-TEST1: Command Output (stdout):
+#  CHECK-TEST1-NEXT: --
+#  CHECK-TEST1-NEXT: # preamble command line
+#  CHECK-TEST1-NEXT: echo "THIS WAS"
+#  CHECK-TEST1-NEXT: # executed command: echo 'THIS WAS'
+#  CHECK-TEST1-NEXT: # .---command stdout{{-*}}
+#  CHECK-TEST1-NEXT: # | THIS WAS
+#  CHECK-TEST1-NEXT: # `---{{-*}}
+#  CHECK-TEST1-NEXT: # preamble command line
+#  CHECK-TEST1-NEXT: echo "INJECTED"
+#  CHECK-TEST1-NEXT: # executed command: echo INJECTED
+#  CHECK-TEST1-NEXT: # .---command stdout{{-*}}
+#  CHECK-TEST1-NEXT: # | INJECTED
+#  CHECK-TEST1-NEXT: # `---{{-*}}
+# CHECK-TEST1-EMPTY:
+#  CHECK-TEST1-NEXT: --
 #
 # CHECK-TEST1: Passed: 1
 
 # RUN: %{lit} %{inputs}/shtest-inject/test-one.txt --show-all | FileCheck --check-prefix=CHECK-TEST2 %s
 #
 # CHECK-TEST2: THIS WAS
 # CHECK-TEST2: INJECTED
 # CHECK-TEST2: IN THE FILE

llvm/utils/lit/tests/shtest-not.py

 # Check the not command
 
 # RUN: not %{lit} -a -v %{inputs}/shtest-not \
 # RUN: | FileCheck -match-full-lines %s
 #
 # END.
 
 # Make sure not and env commands are included in printed commands.
 
 # CHECK: -- Testing: 17 tests{{.*}}
 
 # CHECK: FAIL: shtest-not :: exclamation-args-nested-none.txt {{.*}}
-# CHECK: $ "!" "!" "!"
-# CHECK: Error: '!' requires a subcommand
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: ! ! !
+# CHECK: # executed command: ! ! !
+# CHECK: # | Error: '!' requires a subcommand
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: FAIL: shtest-not :: exclamation-args-none.txt {{.*}}
-# CHECK: $ "!"
-# CHECK: Error: '!' requires a subcommand
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: !
+# CHECK: # executed command: !
+# CHECK: # | Error: '!' requires a subcommand
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: FAIL: shtest-not :: exclamation-calls-external.txt {{.*}}
 
-# CHECK: $ "!" "{{[^"]*}}" "fail.py"
-# CHECK: $ "!" "!" "{{[^"]*}}" "pass.py"
-# CHECK: $ "!" "!" "!" "{{[^"]*}}" "fail.py"
-# CHECK: $ "!" "!" "!" "!" "{{[^"]*}}" "pass.py"
-
-# CHECK: $ "!" "{{[^"]*}}" "pass.py"
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: ! [[PYTHON:.*]] fail.py
+# CHECK: # executed command: ! [[PYTHON_BARE:.*]] fail.py
+# CHECK: ! ! [[PYTHON]] pass.py
+# CHECK: # executed command: ! ! [[PYTHON_BARE]] pass.py
+# CHECK: ! ! ! [[PYTHON]] fail.py
+# CHECK: # executed command: ! ! ! [[PYTHON_BARE]] fail.py
+# CHECK: ! ! ! ! [[PYTHON]] pass.py
+# CHECK: # executed command: ! ! ! ! [[PYTHON_BARE]] pass.py
+
+# CHECK: ! [[PYTHON]] pass.py
+# CHECK: # executed command: ! [[PYTHON_BARE]] pass.py
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: FAIL: shtest-not :: not-args-last-is-crash.txt {{.*}}
-# CHECK: $ "not" "--crash"
-# CHECK: Error: 'not' requires a subcommand
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: not --crash
+# CHECK: # executed command: not --crash
+# CHECK: # | Error: 'not' requires a subcommand
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: FAIL: shtest-not :: not-args-nested-none.txt {{.*}}
-# CHECK: $ "not" "not" "not"
-# CHECK: Error: 'not' requires a subcommand
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: not not not
+# CHECK: # executed command: not not not
+# CHECK: # | Error: 'not' requires a subcommand
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: FAIL: shtest-not :: not-args-none.txt {{.*}}
-# CHECK: $ "not"
-# CHECK: Error: 'not' requires a subcommand
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: not
+# CHECK: # executed command: not
+# CHECK: # | Error: 'not' requires a subcommand
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: FAIL: shtest-not :: not-calls-cd.txt {{.*}}
-# CHECK: $ "not" "not" "cd" "foobar"
-# CHECK: $ "not" "--crash" "cd" "foobar"
-# CHECK: Error: 'not --crash' cannot call 'cd'
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: not not cd foobar
+# CHECK: # executed command: not not cd foobar
+# CHECK: not --crash cd foobar
+# CHECK: # executed command: not --crash cd foobar
+# CHECK: # | Error: 'not --crash' cannot call 'cd'
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: FAIL: shtest-not :: not-calls-colon.txt {{.*}}
-# CHECK: $ "not" "not" ":" "foobar"
-# CHECK: $ "not" "--crash" ":"
-# CHECK: Error: 'not --crash' cannot call ':'
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: not not : foobar
+# CHECK: # executed command: not not : foobar
+# CHECK: not --crash :
+# CHECK: # executed command: not --crash :
+# CHECK: # | Error: 'not --crash' cannot call ':'
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: FAIL: shtest-not :: not-calls-diff-with-crash.txt {{.*}}
-# CHECK: $ "not" "--crash" "diff" "-u" {{.*}}
-# CHECK-NOT: "$"
+# CHECK: not --crash diff -u {{.*}}
+# CHECK: # executed command: not --crash diff -u {{.*}}
+# CHECK-NOT: # executed command: {{.*}}
 # CHECK-NOT: {{[Ee]rror}}
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: # error: command failed with exit status: {{.*}}
+# CHECK-NOT: # executed command: {{.*}}
 # CHECK-NOT: {{[Ee]rror}}
-# CHECK-NOT: "$"
 
 # CHECK: FAIL: shtest-not :: not-calls-diff.txt {{.*}}
-# CHECK: $ "not" "diff" {{.*}}
-# CHECK: $ "not" "not" "not" "diff" {{.*}}
-# CHECK: $ "not" "not" "not" "not" "not" "diff" {{.*}}
-# CHECK: $ "diff" {{.*}}
-# CHECK: $ "not" "not" "diff" {{.*}}
-# CHECK: $ "not" "not" "not" "not" "diff" {{.*}}
-# CHECK: $ "not" "diff" {{.*}}
-# CHECK-NOT: "$"
+# CHECK: not diff {{.*}}
+# CHECK: # executed command: not diff {{.*}}
+# CHECK: not not not diff {{.*}}
+# CHECK: # executed command: not not not diff {{.*}}
+# CHECK: not not not not not diff {{.*}}
+# CHECK: # executed command: not not not not not diff {{.*}}
+# CHECK: diff {{.*}}
+# CHECK: # executed command: diff {{.*}}
+# CHECK: not not diff {{.*}}
+# CHECK: # executed command: not not diff {{.*}}
+# CHECK: not not not not diff {{.*}}
+# CHECK: # executed command: not not not not diff {{.*}}
+# CHECK: not diff {{.*}}
+# CHECK: # executed command: not diff {{.*}}
+# CHECK-NOT: # executed command: {{.*}}
 
 # CHECK: FAIL: shtest-not :: not-calls-echo.txt {{.*}}
-# CHECK: $ "not" "not" "echo" "hello" "world"
-# CHECK: $ "not" "--crash" "echo" "hello" "world"
-# CHECK: Error: 'not --crash' cannot call 'echo'
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: not not echo hello world
+# CHECK: # executed command: not not echo hello world
+# CHECK: not --crash echo hello world
+# CHECK: # executed command: not --crash echo hello world
+# CHECK: # | Error: 'not --crash' cannot call 'echo'
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: FAIL: shtest-not :: not-calls-env-builtin.txt {{.*}}
-# CHECK: $ "not" "--crash" "env" "-u" "FOO" "BAR=3" "rm" "{{.*}}.no-such-file"
-# CHECK: Error: 'env' cannot call 'rm'
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: not --crash env -u FOO BAR=3 rm {{.*}}.no-such-file
+# CHECK: # executed command: not --crash env -u FOO BAR=3 rm {{.+}}.no-such-file{{.*}}
+# CHECK: # | Error: 'env' cannot call 'rm'
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: FAIL: shtest-not :: not-calls-export.txt {{.*}}
-# CHECK: $ "not" "not" "export" "FOO=1"
-# CHECK: $ "not" "--crash" "export" "BAZ=3"
-# CHECK: Error: 'not --crash' cannot call 'export'
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: not not export FOO=1
+# CHECK: # executed command: not not export FOO=1
+# CHECK: not --crash export BAZ=3
+# CHECK: # executed command: not --crash export BAZ=3
+# CHECK: # | Error: 'not --crash' cannot call 'export'
+# CHECK: # error: command failed with exit status: {{.*}}
 
 
 # CHECK: PASS: shtest-not :: not-calls-external.txt {{.*}}
 
-# CHECK: $ "not" "{{[^"]*}}" "fail.py"
-# CHECK: $ "not" "not" "{{[^"]*}}" "pass.py"
-# CHECK: $ "not" "not" "not" "{{[^"]*}}" "fail.py"
-# CHECK: $ "not" "not" "not" "not" "{{[^"]*}}" "pass.py"
-
-# CHECK: $ "not" "not" "--crash" "{{[^"]*}}" "pass.py"
-# CHECK: $ "not" "not" "--crash" "{{[^"]*}}" "fail.py"
-# CHECK: $ "not" "not" "--crash" "not" "{{[^"]*}}" "pass.py"
-# CHECK: $ "not" "not" "--crash" "not" "{{[^"]*}}" "fail.py"
-
-# CHECK: $ "env" "not" "{{[^"]*}}" "fail.py"
-# CHECK: $ "not" "env" "{{[^"]*}}" "fail.py"
-# CHECK: $ "env" "FOO=1" "not" "{{[^"]*}}" "fail.py"
-# CHECK: $ "not" "env" "FOO=1" "BAR=1" "{{[^"]*}}" "fail.py"
-# CHECK: $ "env" "FOO=1" "BAR=1" "not" "env" "-u" "FOO" "BAR=2" "{{[^"]*}}" "fail.py"
-# CHECK: $ "not" "env" "FOO=1" "BAR=1" "not" "env" "-u" "FOO" "-u" "BAR" "{{[^"]*}}" "pass.py"
-# CHECK: $ "not" "not" "env" "FOO=1" "env" "FOO=2" "BAR=1" "{{[^"]*}}" "pass.py"
-# CHECK: $ "env" "FOO=1" "-u" "BAR" "env" "-u" "FOO" "BAR=1" "not" "not" "{{[^"]*}}" "pass.py"
-
-# CHECK: $ "not" "env" "FOO=1" "BAR=1" "env" "FOO=2" "BAR=2" "not" "--crash" "{{[^"]*}}" "pass.py"
-# CHECK: $ "not" "env" "FOO=1" "BAR=1" "not" "--crash" "not" "{{[^"]*}}" "pass.py"
-# CHECK: $ "not" "not" "--crash" "env" "-u" "BAR" "not" "env" "-u" "FOO" "BAR=1" "{{[^"]*}}" "pass.py"
+# CHECK: not [[PYTHON]] fail.py
+# CHECK: # executed command: not [[PYTHON_BARE]] fail.py
+# CHECK: not not [[PYTHON]] pass.py
+# CHECK: # executed command: not not [[PYTHON_BARE]] pass.py
+# CHECK: not not not [[PYTHON]] fail.py
+# CHECK: # executed command: not not not [[PYTHON_BARE]] fail.py
+# CHECK: not not not not [[PYTHON]] pass.py
+# CHECK: # executed command: not not not not [[PYTHON_BARE]] pass.py
+
+# CHECK: not not --crash [[PYTHON]] pass.py
+# CHECK: # executed command: not not --crash [[PYTHON_BARE]] pass.py
+# CHECK: not not --crash [[PYTHON]] fail.py
+# CHECK: # executed command: not not --crash [[PYTHON_BARE]] fail.py
+# CHECK: not not --crash not [[PYTHON]] pass.py
+# CHECK: # executed command: not not --crash not [[PYTHON_BARE]] pass.py
+# CHECK: not not --crash not [[PYTHON]] fail.py
+# CHECK: # executed command: not not --crash not [[PYTHON_BARE]] fail.py
+
+# CHECK: env not [[PYTHON]] fail.py | {{.*}}
+# CHECK: # executed command: env not [[PYTHON_BARE]] fail.py
+# CHECK: not env [[PYTHON]] fail.py | {{.*}}
+# CHECK: # executed command: not env [[PYTHON_BARE]] fail.py
+# CHECK: env FOO=1 not [[PYTHON]] fail.py | {{.*}}
+# CHECK: # executed command: env FOO=1 not [[PYTHON_BARE]] fail.py
+# CHECK: not env FOO=1 BAR=1 [[PYTHON]] fail.py | {{.*}}
+# CHECK: # executed command: not env FOO=1 BAR=1 [[PYTHON_BARE]] fail.py
+# CHECK: env FOO=1 BAR=1 not env -u FOO BAR=2 [[PYTHON]] fail.py | {{.*}}
+# CHECK: # executed command: env FOO=1 BAR=1 not env -u FOO BAR=2 [[PYTHON_BARE]] fail.py
+# CHECK: not env FOO=1 BAR=1 not env -u FOO -u BAR [[PYTHON]] pass.py | {{.*}}
+# CHECK: # executed command: not env FOO=1 BAR=1 not env -u FOO -u BAR [[PYTHON_BARE]] pass.py
+# CHECK: not not env FOO=1 env FOO=2 BAR=1 [[PYTHON]] pass.py | {{.*}}
+# CHECK: # executed command: not not env FOO=1 env FOO=2 BAR=1 [[PYTHON_BARE]] pass.py
+# CHECK: env FOO=1 -u BAR env -u FOO BAR=1 not not [[PYTHON]] pass.py | {{.*}}
+# CHECK: # executed command: env FOO=1 -u BAR env -u FOO BAR=1 not not [[PYTHON_BARE]] pass.py
+
+# CHECK: not env FOO=1 BAR=1 env FOO=2 BAR=2 not --crash [[PYTHON]] pass.py | {{.*}}
+# CHECK: # executed command: not env FOO=1 BAR=1 env FOO=2 BAR=2 not --crash [[PYTHON_BARE]] pass.py
+# CHECK: not env FOO=1 BAR=1 not --crash not [[PYTHON]] pass.py | {{.*}}
+# CHECK: # executed command: not env FOO=1 BAR=1 not --crash not [[PYTHON_BARE]] pass.py
+# CHECK: not not --crash env -u BAR not env -u FOO BAR=1 [[PYTHON]] pass.py | {{.*}}
+# CHECK: # executed command: not not --crash env -u BAR not env -u FOO BAR=1 [[PYTHON_BARE]] pass.py
 
 
 # CHECK: FAIL: shtest-not :: not-calls-fail2.txt {{.*}}
 # CHECK-NEXT: {{.*}} TEST 'shtest-not :: not-calls-fail2.txt' FAILED {{.*}}
 # CHECK-NEXT: Exit Code: 1
 
 # CHECK: FAIL: shtest-not :: not-calls-mkdir.txt {{.*}}
-# CHECK: $ "not" "mkdir" {{.*}}
-# CHECK: $ "not" "--crash" "mkdir" "foobar"
-# CHECK: Error: 'not --crash' cannot call 'mkdir'
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: not mkdir {{.*}}
+# CHECK: # executed command: not mkdir {{.*}}
+# CHECK: not --crash mkdir foobar
+# CHECK: # executed command: not --crash mkdir foobar
+# CHECK: # | Error: 'not --crash' cannot call 'mkdir'
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: FAIL: shtest-not :: not-calls-rm.txt {{.*}}
-# CHECK: $ "not" "rm" {{.*}}
-# CHECK: $ "not" "--crash" "rm" "foobar"
-# CHECK: Error: 'not --crash' cannot call 'rm'
-# CHECK: error: command failed with exit status: {{.*}}
+# CHECK: not rm {{.*}}
+# CHECK: # executed command: not rm {{.*}}
+# CHECK: not --crash rm foobar
+# CHECK: # executed command: not --crash rm foobar
+# CHECK: # | Error: 'not --crash' cannot call 'rm'
+# CHECK: # error: command failed with exit status: {{.*}}
 
 # CHECK: Passed:  1
 # CHECK: Failed: 16
 # CHECK-NOT: {{.}}

llvm/utils/lit/tests/shtest-output-printing.py

 # Check the various features of the ShTest format.
 #
 # RUN: not %{lit} -v %{inputs}/shtest-output-printing > %t.out
-# RUN: FileCheck --input-file %t.out %s
+# RUN: FileCheck --input-file %t.out --match-full-lines %s
 #
 # END.
 
-# CHECK: -- Testing:
-
-# CHECK: FAIL: shtest-output-printing :: basic.txt
-# CHECK-NEXT: *** TEST 'shtest-output-printing :: basic.txt' FAILED ***
-# CHECK-NEXT: Exit Code: 1
-#
-# CHECK:      Command Output
-# CHECK-NEXT: --
-# CHECK-NEXT: $ ":" "RUN: at line 1"
-# CHECK-NEXT: $ "true"
-# CHECK-NEXT: $ ":" "RUN: at line 2"
-# CHECK-NEXT: $ "echo" "hi"
-# CHECK-NEXT: # command output:
-# CHECK-NEXT: hi
-#
-# CHECK:      $ ":" "RUN: at line 3"
-# CHECK-NEXT: $ "not" "not" "wc" "missing-file"
-# CHECK-NEXT: # redirected output from '{{.*(/|\\\\)}}basic.txt.tmp.out':
-# CHECK-NEXT: {{cannot open missing-file|missing-file.* No such file or directory}}
-# CHECK:      note: command had no output on stdout or stderr
-# CHECK-NEXT: error: command failed with exit status: 1
+#       CHECK: -- Testing: {{.*}}
+#       CHECK: FAIL: shtest-output-printing :: basic.txt {{.*}}
+#  CHECK-NEXT: ***{{\**}} TEST 'shtest-output-printing :: basic.txt' FAILED ***{{\**}}
+#  CHECK-NEXT: Exit Code: 1
+# CHECK-EMPTY:
+#  CHECK-NEXT: Command Output (stdout):
+#  CHECK-NEXT: --
+#  CHECK-NEXT: # RUN: at line 1
+#  CHECK-NEXT: true
+#  CHECK-NEXT: # executed command: true
+#  CHECK-NEXT: # RUN: at line 2
+#  CHECK-NEXT: echo hi
+#  CHECK-NEXT: # executed command: echo hi
+#  CHECK-NEXT: # .---command stdout------------
+#  CHECK-NEXT: # | hi
+#  CHECK-NEXT: # `-----------------------------
+#  CHECK-NEXT: # RUN: at line 3
+#  CHECK-NEXT: not not wc missing-file &> [[FILE:.*]] || true
+#  CHECK-NEXT: # executed command: not not wc missing-file
+#  CHECK-NEXT: # .---redirected output from '[[FILE]]'
+#  CHECK-NEXT: # | wc: {{cannot open missing-file|missing-file.* No such file or directory}}
+#  CHECK-NEXT: # `-----------------------------
+#  CHECK-NEXT: # note: command had no output on stdout or stderr
+#  CHECK-NEXT: # error: command failed with exit status: 1
+#  CHECK-NEXT: # executed command: true
+#  CHECK-NEXT: # RUN: at line 4
+#  CHECK-NEXT: not {{.*}}python{{.*}} {{.*}}write-a-lot.py &> [[FILE:.*]]
+#  CHECK-NEXT: # executed command: not {{.*}}python{{.*}} {{.*}}write-a-lot.py{{.*}}
+#  CHECK-NEXT: # .---redirected output from '[[FILE]]'
+#  CHECK-NEXT: # | All work and no play makes Jack a dull boy.
+#  CHECK-NEXT: # | All work and no play makes Jack a dull boy.
+#  CHECK-NEXT: # | All work and no play makes Jack a dull boy.
+#       CHECK: # | ...
+#  CHECK-NEXT: # `---data was truncated--------
+#  CHECK-NEXT: # note: command had no output on stdout or stderr
+#  CHECK-NEXT: # error: command failed with exit status: 1
+# CHECK-EMPTY:
+#  CHECK-NEXT:--

llvm/utils/lit/tests/shtest-pushd-popd.py

 # Check the pushd and popd commands
 
 # RUN: not %{lit} -a -v %{inputs}/shtest-pushd-popd \
 # RUN: | FileCheck -match-full-lines %s
 #
 # END.
 
 # CHECK: -- Testing: 4 tests{{.*}}
 
 # CHECK: FAIL: shtest-pushd-popd :: popd-args.txt ({{[^)]*}})
-# CHECK: $ "popd" "invalid"
-# CHECK: 'popd' does not support arguments
+# CHECK: popd invalid
+# CHECK: # | 'popd' does not support arguments
 
 # CHECK: FAIL: shtest-pushd-popd :: popd-no-stack.txt ({{[^)]*}})
-# CHECK: $ "popd"
-# CHECK: popd: directory stack empty
+# CHECK: popd
+# CHECK: # | popd: directory stack empty
 
 # CHECK: FAIL: shtest-pushd-popd :: pushd-too-many-args.txt ({{[^)]*}})
-# CHECK: $ "pushd" "a" "b"
-# CHECK: 'pushd' supports only one argument
+# CHECK: pushd a b
+# CHECK: # | 'pushd' supports only one argument
 
 # CHECK: Passed:  1
 # CHECK: Failed:  3
 # CHECK-NOT: {{.}}

llvm/utils/lit/tests/shtest-recursive-substitution.py

 # Check that the config.recursiveExpansionLimit is picked up and will cause
 # lit substitutions to be expanded recursively.
 
 # RUN: %{lit} %{inputs}/shtest-recursive-substitution/substitutes-within-limit --show-all | FileCheck --check-prefix=CHECK-TEST1 %s
 # CHECK-TEST1: PASS: substitutes-within-limit :: test.py
-# CHECK-TEST1: $ "echo" "STOP"
+# CHECK-TEST1: echo STOP
 
 # RUN: not %{lit} %{inputs}/shtest-recursive-substitution/does-not-substitute-within-limit --show-all | FileCheck --check-prefix=CHECK-TEST2 %s
 # CHECK-TEST2: UNRESOLVED: does-not-substitute-within-limit :: test.py
 # CHECK-TEST2: ValueError: Recursive substitution of
 
 # RUN: %{lit} %{inputs}/shtest-recursive-substitution/does-not-substitute-no-limit --show-all | FileCheck --check-prefix=CHECK-TEST3 %s
 # CHECK-TEST3: PASS: does-not-substitute-no-limit :: test.py
-# CHECK-TEST3: $ "echo" "%rec4"
+# CHECK-TEST3: echo %rec4
 
 # RUN: not %{lit} %{inputs}/shtest-recursive-substitution/not-an-integer --show-all 2>&1 | FileCheck --check-prefix=CHECK-TEST4 %s
 # CHECK-TEST4: recursiveExpansionLimit must be either None or an integer
 
 # RUN: not %{lit} %{inputs}/shtest-recursive-substitution/negative-integer --show-all 2>&1 | FileCheck --check-prefix=CHECK-TEST5 %s
 # CHECK-TEST5: recursiveExpansionLimit must be a non-negative integer
 
 # RUN: %{lit} %{inputs}/shtest-recursive-substitution/set-to-none --show-all | FileCheck --check-prefix=CHECK-TEST6 %s
 # CHECK-TEST6: PASS: set-to-none :: test.py
 
 # RUN: %{lit} %{inputs}/shtest-recursive-substitution/escaping --show-all | FileCheck --check-prefix=CHECK-TEST7 %s
 # CHECK-TEST7: PASS: escaping :: test.py
-# CHECK-TEST7: $ "echo" "%s" "%s" "%%s"
+# CHECK-TEST7: echo %s %s %%s

llvm/utils/lit/tests/shtest-run-at-line.py

 # CHECK:     RUN: at line 4
 # CHECK:     RUN: at line 6
 # CHECK-NOT: RUN
 
 
 # CHECK-LABEL: FAIL: shtest-run-at-line :: internal-shell/basic.txt
 
 # CHECK:      Command Output (stdout)
-# CHECK:      $ ":" "RUN: at line 1"
-# CHECK-NEXT: $ "true"
-# CHECK-NEXT: $ ":" "RUN: at line 2"
-# CHECK-NEXT: $ "false"
+# CHECK-NEXT: --
+# CHECK-NEXT: # RUN: at line 1
+# CHECK-NEXT: true
+# CHECK-NEXT: # executed command: true
+# CHECK-NEXT: # RUN: at line 2
+# CHECK-NEXT: false
+# CHECK-NEXT: # executed command: false
 # CHECK-NOT:  RUN
 
 # CHECK-LABEL: FAIL: shtest-run-at-line :: internal-shell/line-continuation.txt
 
 # CHECK:      Command Output (stdout)
-# CHECK:      $ ":" "RUN: at line 1"
-# CHECK-NEXT: $ ":" "first" "line" "continued" "to" "second" "line"
-# CHECK-NEXT: $ ":" "RUN: at line 3"
-# CHECK-NEXT: $ "echo" "foo bar"
-# CHECK-NEXT: $ "FileCheck" "{{.*}}"
-# CHECK-NEXT: $ ":" "RUN: at line 5"
-# CHECK-NEXT: $ "echo" "foo baz"
-# CHECK-NEXT: $ "FileCheck" "{{.*}}"
+# CHECK-NEXT: --
+# CHECK-NEXT: # RUN: at line 1
+# CHECK-NEXT: : first line continued to second line
+# CHECK-NEXT: # executed command: : first line continued to second line
+# CHECK-NEXT: # RUN: at line 3
+# CHECK-NEXT: echo 'foo bar' | FileCheck {{.*}}
+# CHECK-NEXT: # executed command: echo 'foo bar'
+# CHECK-NEXT: # executed command: FileCheck {{.*}}
+# CHECK-NEXT: # RUN: at line 5
+# CHECK-NEXT: echo 'foo baz' | FileCheck {{.*}}
+# CHECK-NEXT: # executed command: echo 'foo baz'
+# CHECK-NEXT: # executed command: FileCheck {{.*}}
 # CHECK-NOT:  RUN

llvm/utils/lit/tests/shtest-shell.py

 # RUN: FileCheck --input-file %t.ascii.out %s
 #
 # END.
 
 # CHECK: -- Testing:
 
 # CHECK: FAIL: shtest-shell :: cat-error-0.txt
 # CHECK: *** TEST 'shtest-shell :: cat-error-0.txt' FAILED ***
-# CHECK: $ "cat" "-b" "temp1.txt"
-# CHECK: # command stderr:
-# CHECK: Unsupported: 'cat':  option -b not recognized
-# CHECK: error: command failed with exit status: 1
+# CHECK: cat -b temp1.txt
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | Unsupported: 'cat':  option -b not recognized
+# CHECK: # error: command failed with exit status: 1
 # CHECK: ***
 
 # CHECK: FAIL: shtest-shell :: cat-error-1.txt
 # CHECK: *** TEST 'shtest-shell :: cat-error-1.txt' FAILED ***
-# CHECK: $ "cat" "temp1.txt"
-# CHECK: # command stderr:
-# CHECK: [Errno 2] No such file or directory: 'temp1.txt'
-# CHECK: error: command failed with exit status: 1
+# CHECK: cat temp1.txt
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | [Errno 2] No such file or directory: 'temp1.txt'
+# CHECK: # error: command failed with exit status: 1
 # CHECK: ***
 
 # CHECK: FAIL: shtest-shell :: colon-error.txt
 # CHECK: *** TEST 'shtest-shell :: colon-error.txt' FAILED ***
-# CHECK: $ ":"
-# CHECK: # command stderr:
-# CHECK: Unsupported: ':' cannot be part of a pipeline
-# CHECK: error: command failed with exit status: 127
+# CHECK: :
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | Unsupported: ':' cannot be part of a pipeline
+# CHECK: # error: command failed with exit status: 127
 # CHECK: ***
 
 # CHECK: PASS: shtest-shell :: continuations.txt
 
 # CHECK: PASS: shtest-shell :: dev-null.txt
 
-# CHECK: FAIL: shtest-shell :: diff-b.txt
-# CHECK: *** TEST 'shtest-shell :: diff-b.txt' FAILED ***
-# CHECK: $ "diff" "-b" "{{[^"]*}}.0" "{{[^"]*}}.1"
-# CHECK: # command output:
-# CHECK: 1,2
-# CHECK-NEXT: {{^  }}f o o
-# CHECK-NEXT: ! b a r
-# CHECK-NEXT: ---
-# CHECK-NEXT: {{^  }}f o o
-# CHECK-NEXT: ! bar
-# CHECK-EMPTY:
-# CHECK: error: command failed with exit status: 1
-# CHECK: ***
+#      CHECK: FAIL: shtest-shell :: diff-b.txt
+#      CHECK: *** TEST 'shtest-shell :: diff-b.txt' FAILED ***
+#      CHECK: diff -b {{[^"]*}}.0 {{[^"]*}}.1
+#      CHECK: # .---command stdout{{-*}}
+#      CHECK: # | {{.*}}1,2
+# CHECK-NEXT: # |   f o o
+# CHECK-NEXT: # | ! b a r
+# CHECK-NEXT: # | ---
+# CHECK-NEXT: # |   f o o
+# CHECK-NEXT: # | ! bar
+# CHECK-NEXT: # `---{{-*}}
+# CHECK-NEXT: # error: command failed with exit status: 1
+#      CHECK: ***
 
 
 # CHECK: FAIL: shtest-shell :: diff-encodings.txt
 # CHECK: *** TEST 'shtest-shell :: diff-encodings.txt' FAILED ***
 
-# CHECK: $ "diff" "-u" "diff-in.bin" "diff-in.bin"
-# CHECK-NOT: error
-
-# CHECK: $ "diff" "-u" "diff-in.utf16" "diff-in.bin"
-# CHECK: # command output:
-# CHECK-NEXT: ---
-# CHECK-NEXT: +++
-# CHECK-NEXT: @@
-# CHECK-NEXT: {{^ .f.o.o.$}}
-# CHECK-NEXT: {{^-.b.a.r.$}}
-# CHECK-NEXT: {{^\+.b.a.r.}}
-# CHECK-NEXT: {{^ .b.a.z.$}}
-# CHECK: error: command failed with exit status: 1
-# CHECK: $ "true"
-
-# CHECK: $ "diff" "-u" "diff-in.utf8" "diff-in.bin"
-# CHECK: # command output:
-# CHECK-NEXT: ---
-# CHECK-NEXT: +++
-# CHECK-NEXT: @@
-# CHECK-NEXT: -foo
-# CHECK-NEXT: -bar
-# CHECK-NEXT: -baz
-# CHECK-NEXT: {{^\+.f.o.o.$}}
-# CHECK-NEXT: {{^\+.b.a.r.}}
-# CHECK-NEXT: {{^\+.b.a.z.$}}
-# CHECK: error: command failed with exit status: 1
-# CHECK: $ "true"
-
-# CHECK: $ "diff" "-u" "diff-in.bin" "diff-in.utf8"
-# CHECK: # command output:
-# CHECK-NEXT: ---
-# CHECK-NEXT: +++
-# CHECK-NEXT: @@
-# CHECK-NEXT: {{^\-.f.o.o.$}}
-# CHECK-NEXT: {{^\-.b.a.r.}}
-# CHECK-NEXT: {{^\-.b.a.z.$}}
-# CHECK-NEXT: +foo
-# CHECK-NEXT: +bar
-# CHECK-NEXT: +baz
-# CHECK: error: command failed with exit status: 1
-# CHECK: $ "true"
-
-# CHECK: $ "cat" "diff-in.bin"
-# CHECK-NOT: error
-# CHECK: $ "diff" "-u" "-" "diff-in.bin"
-# CHECK-NOT: error
+#      CHECK: diff -u diff-in.bin diff-in.bin
+# CHECK-NEXT: # executed command: diff -u diff-in.bin diff-in.bin
+#  CHECK-NOT: error
 
-# CHECK: $ "cat" "diff-in.bin"
-# CHECK-NOT: error
-# CHECK: $ "diff" "-u" "diff-in.bin" "-"
-# CHECK-NOT: error
+#      CHECK: diff -u diff-in.utf16 diff-in.bin && false || true
+# CHECK-NEXT: # executed command: diff -u diff-in.utf16 diff-in.bin
+# CHECK-NEXT: # .---command stdout{{-*}}
+# CHECK-NEXT: # | ---
+# CHECK-NEXT: # | +++
+# CHECK-NEXT: # | @@
+# CHECK-NEXT: # | {{.f.o.o.$}}
+# CHECK-NEXT: # | {{-.b.a.r.$}}
+# CHECK-NEXT: # | {{\+.b.a.r.}}
+# CHECK-NEXT: # | {{.b.a.z.$}}
+# CHECK-NEXT: # `---{{-*}}
+# CHECK-NEXT: # error: command failed with exit status: 1
+# CHECK-NEXT: # executed command: true
+
+#      CHECK: diff -u diff-in.utf8 diff-in.bin && false || true
+# CHECK-NEXT: # executed command: diff -u diff-in.utf8 diff-in.bin
+# CHECK-NEXT: # .---command stdout{{-*}}
+# CHECK-NEXT: # | ---
+# CHECK-NEXT: # | +++
+# CHECK-NEXT: # | @@
+# CHECK-NEXT: # | -foo
+# CHECK-NEXT: # | -bar
+# CHECK-NEXT: # | -baz
+# CHECK-NEXT: # | {{\+.f.o.o.$}}
+# CHECK-NEXT: # | {{\+.b.a.r.}}
+# CHECK-NEXT: # | {{\+.b.a.z.$}}
+# CHECK-NEXT: # `---{{-*}}
+# CHECK-NEXT: # error: command failed with exit status: 1
+# CHECK-NEXT: # executed command: true
+
+#      CHECK: diff -u diff-in.bin diff-in.utf8 && false || true
+# CHECK-NEXT: # executed command: diff -u diff-in.bin diff-in.utf8
+# CHECK-NEXT: # .---command stdout{{-*}}
+# CHECK-NEXT: # | ---
+# CHECK-NEXT: # | +++
+# CHECK-NEXT: # | @@
+# CHECK-NEXT: # | {{-.f.o.o.$}}
+# CHECK-NEXT: # | {{-.b.a.r.}}
+# CHECK-NEXT: # | {{-.b.a.z.$}}
+# CHECK-NEXT: # | +foo
+# CHECK-NEXT: # | +bar
+# CHECK-NEXT: # | +baz
+# CHECK-NEXT: # `---{{-*}}
+# CHECK-NEXT: # error: command failed with exit status: 1
+# CHECK-NEXT: # executed command: true
+
+#     CHECK: cat diff-in.bin | diff -u - diff-in.bin
+# CHECK-NOT: error
+
+#     CHECK: cat diff-in.bin | diff -u diff-in.bin -
+# CHECK-NOT: error
+
+#      CHECK: cat diff-in.bin | diff -u diff-in.utf16 - && false || true
+# CHECK-NEXT: # executed command: cat diff-in.bin
+# CHECK-NEXT: # executed command: diff -u diff-in.utf16 -
+# CHECK-NEXT: # .---command stdout{{-*}}
+# CHECK-NEXT: # | ---
+# CHECK-NEXT: # | +++
+# CHECK-NEXT: # | @@
+# CHECK-NEXT: # | {{.f.o.o.$}}
+# CHECK-NEXT: # | {{-.b.a.r.$}}
+# CHECK-NEXT: # | {{\+.b.a.r.}}
+# CHECK-NEXT: # | {{.b.a.z.$}}
+# CHECK-NEXT: # `---{{-*}}
+# CHECK-NEXT: # error: command failed with exit status: 1
+# CHECK-NEXT: # executed command: true
+
+#      CHECK: cat diff-in.bin | diff -u diff-in.utf8 - && false || true
+# CHECK-NEXT: # executed command: cat diff-in.bin
+# CHECK-NEXT: # executed command: diff -u diff-in.utf8 -
+# CHECK-NEXT: # .---command stdout{{-*}}
+# CHECK-NEXT: # | ---
+# CHECK-NEXT: # | +++
+# CHECK-NEXT: # | @@
+# CHECK-NEXT: # | -foo
+# CHECK-NEXT: # | -bar
+# CHECK-NEXT: # | -baz
+# CHECK-NEXT: # | {{\+.f.o.o.$}}
+# CHECK-NEXT: # | {{\+.b.a.r.}}
+# CHECK-NEXT: # | {{\+.b.a.z.$}}
+# CHECK-NEXT: # `---{{-*}}
+# CHECK-NEXT: # error: command failed with exit status: 1
+# CHECK-NEXT: # executed command: true
+
+#      CHECK: cat diff-in.bin | diff -u - diff-in.utf8 && false || true
+# CHECK-NEXT: # executed command: cat diff-in.bin
+# CHECK-NEXT: # executed command: diff -u - diff-in.utf8
+# CHECK-NEXT: # .---command stdout{{-*}}
+# CHECK-NEXT: # | ---
+# CHECK-NEXT: # | +++
+# CHECK-NEXT: # | @@
+# CHECK-NEXT: # | {{-.f.o.o.$}}
+# CHECK-NEXT: # | {{-.b.a.r.}}
+# CHECK-NEXT: # | {{-.b.a.z.$}}
+# CHECK-NEXT: # | +foo
+# CHECK-NEXT: # | +bar
+# CHECK-NEXT: # | +baz
+# CHECK-NEXT: # `---{{-*}}
+# CHECK-NEXT: # error: command failed with exit status: 1
+# CHECK-NEXT: # executed command: true
 
-# CHECK: $ "cat" "diff-in.bin"
-# CHECK-NOT: error
-# CHECK: $ "diff" "-u" "diff-in.utf16" "-"
-# CHECK: # command output:
-# CHECK-NEXT: ---
-# CHECK-NEXT: +++
-# CHECK-NEXT: @@
-# CHECK-NEXT: {{^ .f.o.o.$}}
-# CHECK-NEXT: {{^-.b.a.r.$}}
-# CHECK-NEXT: {{^\+.b.a.r.}}
-# CHECK-NEXT: {{^ .b.a.z.$}}
-# CHECK: error: command failed with exit status: 1
-# CHECK: $ "true"
-
-# CHECK: $ "cat" "diff-in.bin"
-# CHECK-NOT: error
-# CHECK: $ "diff" "-u" "diff-in.utf8" "-"
-# CHECK: # command output:
-# CHECK-NEXT: ---
-# CHECK-NEXT: +++
-# CHECK-NEXT: @@
-# CHECK-NEXT: -foo
-# CHECK-NEXT: -bar
-# CHECK-NEXT: -baz
-# CHECK-NEXT: {{^\+.f.o.o.$}}
-# CHECK-NEXT: {{^\+.b.a.r.}}
-# CHECK-NEXT: {{^\+.b.a.z.$}}
-# CHECK: error: command failed with exit status: 1
-# CHECK: $ "true"
-
-# CHECK: $ "diff" "-u" "-" "diff-in.utf8"
-# CHECK: # command output:
-# CHECK-NEXT: ---
-# CHECK-NEXT: +++
-# CHECK-NEXT: @@
-# CHECK-NEXT: {{^\-.f.o.o.$}}
-# CHECK-NEXT: {{^\-.b.a.r.}}
-# CHECK-NEXT: {{^\-.b.a.z.$}}
-# CHECK-NEXT: +foo
-# CHECK-NEXT: +bar
-# CHECK-NEXT: +baz
-# CHECK: error: command failed with exit status: 1
-# CHECK: $ "true"
-
-# CHECK: $ "false"
+# CHECK: false
 
 # CHECK: ***
 
 
 # CHECK: FAIL: shtest-shell :: diff-error-1.txt
 # CHECK: *** TEST 'shtest-shell :: diff-error-1.txt' FAILED ***
-# CHECK: $ "diff" "-B" "temp1.txt" "temp2.txt"
-# CHECK: # command stderr:
-# CHECK: Unsupported: 'diff': option -B not recognized
-# CHECK: error: command failed with exit status: 1
+# CHECK: diff -B temp1.txt temp2.txt
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | Unsupported: 'diff': option -B not recognized
+# CHECK: # error: command failed with exit status: 1
 # CHECK: ***
 
 # CHECK: FAIL: shtest-shell :: diff-error-2.txt
 # CHECK: *** TEST 'shtest-shell :: diff-error-2.txt' FAILED ***
-# CHECK: $ "diff" "temp.txt"
-# CHECK: # command stderr:
-# CHECK: Error: missing or extra operand
-# CHECK: error: command failed with exit status: 1
+# CHECK: diff temp.txt
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | Error: missing or extra operand
+# CHECK: # error: command failed with exit status: 1
 # CHECK: ***
 
 # CHECK: FAIL: shtest-shell :: diff-error-3.txt
 # CHECK: *** TEST 'shtest-shell :: diff-error-3.txt' FAILED ***
-# CHECK: $ "diff" "temp.txt" "temp1.txt"
-# CHECK: # command stderr:
-# CHECK: Error: 'diff' command failed
+# CHECK: diff temp.txt temp1.txt
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | Error: 'diff' command failed
 # CHECK: error: command failed with exit status: 1
 # CHECK: ***
 
-# CHECK: FAIL: shtest-shell :: diff-error-4.txt
-# CHECK: *** TEST 'shtest-shell :: diff-error-4.txt' FAILED ***
-# CHECK: Exit Code: 1
-# CHECK: # command output:
-# CHECK: diff-error-4.txt.tmp
-# CHECK: diff-error-4.txt.tmp1
-# CHECK: *** 1 ****
-# CHECK: ! hello-first
-# CHECK: --- 1 ----
-# CHECK: ! hello-second
-# CHECK: ***
+#      CHECK: FAIL: shtest-shell :: diff-error-4.txt
+#      CHECK: *** TEST 'shtest-shell :: diff-error-4.txt' FAILED ***
+#      CHECK: Exit Code: 1
+#      CHECK: # .---command stdout{{-*}}
+# CHECK-NEXT: # | {{.*}}diff-error-4.txt.tmp
+# CHECK-NEXT: # | {{.*}}diff-error-4.txt.tmp1
+# CHECK-NEXT: # | {{\*+}}
+# CHECK-NEXT: # | *** 1 ****
+# CHECK-NEXT: # | ! hello-first
+# CHECK-NEXT: # | --- 1 ----
+# CHECK-NEXT: # | ! hello-second
+# CHECK-NEXT: # `---{{-*}}
+#      CHECK: ***
 
 # CHECK: FAIL: shtest-shell :: diff-error-5.txt
 # CHECK: *** TEST 'shtest-shell :: diff-error-5.txt' FAILED ***
-# CHECK: $ "diff"
-# CHECK: # command stderr:
-# CHECK: Error: missing or extra operand
-# CHECK: error: command failed with exit status: 1
+# CHECK: diff
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | Error: missing or extra operand
+# CHECK: # error: command failed with exit status: 1
 # CHECK: ***
 
 # CHECK: FAIL: shtest-shell :: diff-error-6.txt
 # CHECK: *** TEST 'shtest-shell :: diff-error-6.txt' FAILED ***
-# CHECK: $ "diff"
-# CHECK: # command stderr:
-# CHECK: Error: missing or extra operand
-# CHECK: error: command failed with exit status: 1
+# CHECK: diff
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | Error: missing or extra operand
+# CHECK: # error: command failed with exit status: 1
 # CHECK: ***
 
 
 # CHECK: FAIL: shtest-shell :: diff-pipes.txt
 
 # CHECK: *** TEST 'shtest-shell :: diff-pipes.txt' FAILED ***
 
-# CHECK: $ "diff" "{{[^"]*}}.foo" "{{[^"]*}}.foo"
-# CHECK-NOT: note
-# CHECK-NOT: error
-# CHECK: $ "FileCheck"
+# CHECK: diff {{[^ ]*}}.foo {{.*}}.foo | FileCheck {{.*}}
 # CHECK-NOT: note
 # CHECK-NOT: error
 
-# CHECK: $ "diff" "-u" "{{[^"]*}}.foo" "{{[^"]*}}.bar"
-# CHECK: note: command had no output on stdout or stderr
-# CHECK: error: command failed with exit status: 1
-# CHECK: $ "FileCheck"
-# CHECK-NOT: note
-# CHECK-NOT: error
-# CHECK: $ "true"
+#      CHECK: diff -u {{.*}}.foo {{.*}}.bar | FileCheck {{.*}} && false || true
+# CHECK-NEXT: # executed command: diff -u {{.+}}.foo{{.*}} {{.+}}.bar{{.*}}
+# CHECK-NEXT: # note: command had no output on stdout or stderr
+# CHECK-NEXT: # error: command failed with exit status: 1
+# CHECK-NEXT: # executed command: FileCheck
+# CHECK-NEXT: # executed command: true
 
-# CHECK: $ "cat" "{{[^"]*}}.foo"
-# CHECK: $ "diff" "-u" "-" "{{[^"]*}}.foo"
+#     CHECK: cat {{.*}}.foo | diff -u - {{.*}}.foo
 # CHECK-NOT: note
 # CHECK-NOT: error
 
-# CHECK: $ "cat" "{{[^"]*}}.foo"
-# CHECK: $ "diff" "-u" "{{[^"]*}}.foo" "-"
+#     CHECK: cat {{.*}}.foo | diff -u {{.*}}.foo -
 # CHECK-NOT: note
 # CHECK-NOT: error
 
-# CHECK: $ "cat" "{{[^"]*}}.bar"
-# CHECK: $ "diff" "-u" "{{[^"]*}}.foo" "-"
-# CHECK: # command output:
-# CHECK: @@
-# CHECK-NEXT: -foo
-# CHECK-NEXT: +bar
-# CHECK: error: command failed with exit status: 1
-# CHECK: $ "true"
-
-# CHECK: $ "cat" "{{[^"]*}}.bar"
-# CHECK: $ "diff" "-u" "-" "{{[^"]*}}.foo"
-# CHECK: # command output:
-# CHECK: @@
-# CHECK-NEXT: -bar
-# CHECK-NEXT: +foo
-# CHECK: error: command failed with exit status: 1
-# CHECK: $ "true"
+#      CHECK: cat {{.*}}.bar | diff -u {{.*}}.foo - && false || true
+# CHECK-NEXT: # executed command: cat {{.+}}.bar{{.*}}
+# CHECK-NEXT: # executed command: diff -u {{.+}}.foo{{.*}} -
+# CHECK-NEXT: # .---command stdout{{-*}}
+#      CHECK: # | @@
+# CHECK-NEXT: # | -foo
+# CHECK-NEXT: # | +bar
+# CHECK-NEXT: # `---{{-*}}
+# CHECK-NEXT: # error: command failed with exit status: 1
+# CHECK-NEXT: # executed command: true
+
+#      CHECK: cat {{.*}}.bar | diff -u - {{.*}}.foo && false || true
+# CHECK-NEXT: # executed command: cat {{.+}}.bar{{.*}}
+# CHECK-NEXT: # executed command: diff -u - {{.+}}.foo{{.*}}
+# CHECK-NEXT: # .---command stdout{{-*}}
+#      CHECK: # | @@
+# CHECK-NEXT: # | -bar
+# CHECK-NEXT: # | +foo
+# CHECK-NEXT: # `---{{-*}}
+# CHECK-NEXT: # error: command failed with exit status: 1
+# CHECK-NEXT: # executed command: true
 
-# CHECK: $ "cat" "{{[^"]*}}.foo"
-# CHECK: $ "diff" "-" "{{[^"]*}}.foo"
-# CHECK-NOT: note
-# CHECK-NOT: error
-# CHECK: $ "FileCheck"
+#     CHECK: cat {{.*}}.foo | diff - {{.*}}.foo | FileCheck {{.*}}
 # CHECK-NOT: note
 # CHECK-NOT: error
 
-# CHECK: $ "cat" "{{[^"]*}}.bar"
-# CHECK: $ "diff" "-u" "{{[^"]*}}.foo" "-"
-# CHECK: note: command had no output on stdout or stderr
-# CHECK: error: command failed with exit status: 1
-# CHECK: $ "FileCheck"
-# CHECK-NOT: note
-# CHECK-NOT: error
-# CHECK: $ "true"
+#      CHECK: cat {{.*}}.bar | diff -u {{.*}}.foo - | FileCheck {{.*}}
+# CHECK-NEXT: # executed command: cat {{.+}}.bar{{.*}}
+# CHECK-NEXT: # executed command: diff -u {{.+}}.foo{{.*}} -
+# CHECK-NEXT: note: command had no output on stdout or stderr
+# CHECK-NEXT: error: command failed with exit status: 1
+# CHECK-NEXT: # executed command: FileCheck
+# CHECK-NEXT: # executed command: true
 
-# CHECK: $ "false"
+# CHECK: false
 
 # CHECK: ***
 
 
 # CHECK: FAIL: shtest-shell :: diff-r-error-0.txt
 # CHECK: *** TEST 'shtest-shell :: diff-r-error-0.txt' FAILED ***
-# CHECK: $ "diff" "-r"
-# CHECK: # command output:
-# CHECK: Only in {{.*}}dir1: dir1unique
-# CHECK: Only in {{.*}}dir2: dir2unique
-# CHECK: error: command failed with exit status: 1
+# CHECK: diff -r
+# CHECK: # .---command stdout{{-*}}
+# CHECK: # | Only in {{.*}}dir1: dir1unique
+# CHECK: # | Only in {{.*}}dir2: dir2unique
+# CHECK: # error: command failed with exit status: 1
 
 # CHECK: FAIL: shtest-shell :: diff-r-error-1.txt
 # CHECK: *** TEST 'shtest-shell :: diff-r-error-1.txt' FAILED ***
-# CHECK: $ "diff" "-r"
-# CHECK: # command output:
-# CHECK: *** {{.*}}dir1{{.*}}subdir{{.*}}f01
-# CHECK: --- {{.*}}dir2{{.*}}subdir{{.*}}f01
-# CHECK: 12345
-# CHECK: 00000
-# CHECK: error: command failed with exit status: 1
+# CHECK: diff -r
+# CHECK: # .---command stdout{{-*}}
+# CHECK: # | *** {{.*}}dir1{{.*}}subdir{{.*}}f01
+# CHECK: # | --- {{.*}}dir2{{.*}}subdir{{.*}}f01
+# CHECK: # | ! 12345
+# CHECK: # | ! 00000
+# CHECK: # error: command failed with exit status: 1
 
 # CHECK: FAIL: shtest-shell :: diff-r-error-2.txt
 # CHECK: *** TEST 'shtest-shell :: diff-r-error-2.txt' FAILED ***
-# CHECK: $ "diff" "-r"
-# CHECK: # command output:
-# CHECK: Only in {{.*}}dir2: extrafile
-# CHECK: error: command failed with exit status: 1
+# CHECK: diff -r
+# CHECK: # .---command stdout{{-*}}
+# CHECK: # | Only in {{.*}}dir2: extrafile
+# CHECK: # error: command failed with exit status: 1
 
 # CHECK: FAIL: shtest-shell :: diff-r-error-3.txt
 # CHECK: *** TEST 'shtest-shell :: diff-r-error-3.txt' FAILED ***
-# CHECK: $ "diff" "-r"
-# CHECK: # command output:
-# CHECK: Only in {{.*}}dir1: extra_subdir
-# CHECK: error: command failed with exit status: 1
+# CHECK: diff -r
+# CHECK: # .---command stdout{{-*}}
+# CHECK: # | Only in {{.*}}dir1: extra_subdir
+# CHECK: # error: command failed with exit status: 1
 
 # CHECK: FAIL: shtest-shell :: diff-r-error-4.txt
 # CHECK: *** TEST 'shtest-shell :: diff-r-error-4.txt' FAILED ***
-# CHECK: $ "diff" "-r"
-# CHECK: # command output:
-# CHECK: File {{.*}}dir1{{.*}}extra_subdir is a directory while file {{.*}}dir2{{.*}}extra_subdir is a regular file
-# CHECK: error: command failed with exit status: 1
+# CHECK: diff -r
+# CHECK: # .---command stdout{{-*}}
+# CHECK: # | File {{.*}}dir1{{.*}}extra_subdir is a directory while file {{.*}}dir2{{.*}}extra_subdir is a regular file
+# CHECK: # error: command failed with exit status: 1
 
 # CHECK: FAIL: shtest-shell :: diff-r-error-5.txt
 # CHECK: *** TEST 'shtest-shell :: diff-r-error-5.txt' FAILED ***
-# CHECK: $ "diff" "-r"
-# CHECK: # command output:
-# CHECK: Only in {{.*}}dir1: extra_subdir
-# CHECK: error: command failed with exit status: 1
+# CHECK: diff -r
+# CHECK: # .---command stdout{{-*}}
+# CHECK: # | Only in {{.*}}dir1: extra_subdir
+# CHECK: # error: command failed with exit status: 1
 
 # CHECK: FAIL: shtest-shell :: diff-r-error-6.txt
 # CHECK: *** TEST 'shtest-shell :: diff-r-error-6.txt' FAILED ***
-# CHECK: $ "diff" "-r"
-# CHECK: # command output:
-# CHECK: File {{.*}}dir1{{.*}}extra_file is a regular empty file while file {{.*}}dir2{{.*}}extra_file is a directory
-# CHECK: error: command failed with exit status: 1
+# CHECK: diff -r
+# CHECK: # .---command stdout{{-*}}
+# CHECK: # | File {{.*}}dir1{{.*}}extra_file is a regular empty file while file {{.*}}dir2{{.*}}extra_file is a directory
+# CHECK: # error: command failed with exit status: 1
 
 # CHECK: FAIL: shtest-shell :: diff-r-error-7.txt
 # CHECK: *** TEST 'shtest-shell :: diff-r-error-7.txt' FAILED ***
-# CHECK: $ "diff" "-r" "-" "{{[^"]*}}"
-# CHECK: # command stderr:
-# CHECK: Error: cannot recursively compare '-'
-# CHECK: error: command failed with exit status: 1
+# CHECK: diff -r - {{.*}}
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | Error: cannot recursively compare '-'
+# CHECK: # error: command failed with exit status: 1
 
 # CHECK: FAIL: shtest-shell :: diff-r-error-8.txt
 # CHECK: *** TEST 'shtest-shell :: diff-r-error-8.txt' FAILED ***
-# CHECK: $ "diff" "-r" "{{[^"]*}}" "-"
-# CHECK: # command stderr:
-# CHECK: Error: cannot recursively compare '-'
-# CHECK: error: command failed with exit status: 1
+# CHECK: diff -r {{.*}} -
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | Error: cannot recursively compare '-'
+# CHECK: # error: command failed with exit status: 1
 
 # CHECK: PASS: shtest-shell :: diff-r.txt
 
 
 # CHECK: FAIL: shtest-shell :: diff-strip-trailing-cr.txt
 
 # CHECK: *** TEST 'shtest-shell :: diff-strip-trailing-cr.txt' FAILED ***
 
-# CHECK: $ "diff" "-u" "diff-in.dos" "diff-in.unix"
-# CHECK: # command output:
-# CHECK: @@
-# CHECK-NEXT: -In this file, the
-# CHECK-NEXT: -sequence "\r\n"
-# CHECK-NEXT: -terminates lines.
-# CHECK-NEXT: +In this file, the
-# CHECK-NEXT: +sequence "\n"
-# CHECK-NEXT: +terminates lines.
-# CHECK: error: command failed with exit status: 1
-# CHECK: $ "true"
-
-# CHECK: $ "diff" "-u" "diff-in.unix" "diff-in.dos"
-# CHECK: # command output:
-# CHECK: @@
-# CHECK-NEXT: -In this file, the
-# CHECK-NEXT: -sequence "\n"
-# CHECK-NEXT: -terminates lines.
-# CHECK-NEXT: +In this file, the
-# CHECK-NEXT: +sequence "\r\n"
-# CHECK-NEXT: +terminates lines.
-# CHECK: error: command failed with exit status: 1
-# CHECK: $ "true"
+#      CHECK: diff -u diff-in.dos diff-in.unix && false || true
+# CHECK-NEXT: # executed command: diff -u diff-in.dos diff-in.unix
+# CHECK-NEXT: # .---command stdout{{-*}}
+#      CHECK: # | @@
+# CHECK-NEXT: # | -In this file, the
+# CHECK-NEXT: # | -sequence "\r\n"
+# CHECK-NEXT: # | -terminates lines.
+# CHECK-NEXT: # | +In this file, the
+# CHECK-NEXT: # | +sequence "\n"
+# CHECK-NEXT: # | +terminates lines.
+# CHECK-NEXT: # `---{{-*}}
+# CHECK-NEXT: # error: command failed with exit status: 1
+# CHECK-NEXT: # executed command: true
+
+#      CHECK: diff -u diff-in.unix diff-in.dos && false || true
+# CHECK-NEXT: # executed command: diff -u diff-in.unix diff-in.dos
+# CHECK-NEXT: # .---command stdout{{-*}}
+#      CHECK: # | @@
+# CHECK-NEXT: # | -In this file, the
+# CHECK-NEXT: # | -sequence "\n"
+# CHECK-NEXT: # | -terminates lines.
+# CHECK-NEXT: # | +In this file, the
+# CHECK-NEXT: # | +sequence "\r\n"
+# CHECK-NEXT: # | +terminates lines.
+# CHECK-NEXT: # `---{{-*}}
+# CHECK-NEXT: # error: command failed with exit status: 1
+# CHECK-NEXT: # executed command: true
+
+#      CHECK: diff -u --strip-trailing-cr diff-in.dos diff-in.unix && false || true
+# CHECK-NEXT: executed command: diff -u --strip-trailing-cr diff-in.dos diff-in.unix
+# CHECK-NEXT: # .---command stdout{{-*}}
+#      CHECK: # | @@
+# CHECK-NEXT: # |  In this file, the
+# CHECK-NEXT: # | -sequence "\r\n"
+# CHECK-NEXT: # | +sequence "\n"
+# CHECK-NEXT: # |  terminates lines.
+# CHECK-NEXT: # `---{{-*}}
+# CHECK-NEXT: # error: command failed with exit status: 1
+# CHECK-NEXT: # executed command: true
+
+#      CHECK: diff -u --strip-trailing-cr diff-in.unix diff-in.dos && false || true
+# CHECK-NEXT: # executed command: diff -u --strip-trailing-cr diff-in.unix diff-in.dos
+# CHECK-NEXT: # .---command stdout{{-*}}
+#      CHECK: # | @@
+# CHECK-NEXT: # |  In this file, the
+# CHECK-NEXT: # | -sequence "\n"
+# CHECK-NEXT: # | +sequence "\r\n"
+# CHECK-NEXT: # |  terminates lines.
+# CHECK-NEXT: # `---{{-*}}
+# CHECK-NEXT: # error: command failed with exit status: 1
+# CHECK-NEXT: # executed command: true
 
-# CHECK: $ "diff" "-u" "--strip-trailing-cr" "diff-in.dos" "diff-in.unix"
-# CHECK: # command output:
-# CHECK: @@
-# CHECK-NEXT:  In this file, the
-# CHECK-NEXT: -sequence "\r\n"
-# CHECK-NEXT: +sequence "\n"
-# CHECK-NEXT:  terminates lines.
-# CHECK: error: command failed with exit status: 1
-# CHECK: $ "true"
-
-# CHECK: $ "diff" "-u" "--strip-trailing-cr" "diff-in.unix" "diff-in.dos"
-# CHECK: # command output:
-# CHECK: @@
-# CHECK-NEXT:  In this file, the
-# CHECK-NEXT: -sequence "\n"
-# CHECK-NEXT: +sequence "\r\n"
-# CHECK-NEXT:  terminates lines.
-# CHECK: error: command failed with exit status: 1
-# CHECK: $ "true"
-
-# CHECK: $ "false"
+# CHECK: false
 
 # CHECK: ***
 
 
 # CHECK: FAIL: shtest-shell :: diff-unified.txt
 
 # CHECK: *** TEST 'shtest-shell :: diff-unified.txt' FAILED ***
 
-# CHECK: $ "diff" "-u" "{{[^"]*}}.foo" "{{[^"]*}}.bar"
-# CHECK: # command output:
-# CHECK: @@ {{.*}} @@
-# CHECK-NEXT: 3
-# CHECK-NEXT: 4
-# CHECK-NEXT: 5
-# CHECK-NEXT: -6 foo
-# CHECK-NEXT: +6 bar
-# CHECK-NEXT: 7
-# CHECK-NEXT: 8
-# CHECK-NEXT: 9
-# CHECK-EMPTY:
-# CHECK-NEXT: error: command failed with exit status: 1
-# CHECK-NEXT: $ "true"
+#      CHECK: diff -u {{.*}}.foo {{.*}}.bar && false || true
+# CHECK-NEXT: # executed command: diff -u {{.+}}.foo{{.*}} {{.+}}.bar{{.*}}
+# CHECK-NEXT: # .---command stdout{{-*}}
+#      CHECK: # | @@ {{.*}} @@
+# CHECK-NEXT: # | 3
+# CHECK-NEXT: # | 4
+# CHECK-NEXT: # | 5
+# CHECK-NEXT: # | -6 foo
+# CHECK-NEXT: # | +6 bar
+# CHECK-NEXT: # | 7
+# CHECK-NEXT: # | 8
+# CHECK-NEXT: # | 9
+# CHECK-NEXT: # `---{{-*}}
+# CHECK-NEXT: # error: command failed with exit status: 1
+# CHECK-NEXT: # executed command: true
+
+#      CHECK: diff -U 2 {{.*}}.foo {{.*}}.bar && false || true
+# CHECK-NEXT: # executed command: diff -U 2 {{.+}}.foo{{.*}} {{.+}}.bar{{.*}}
+# CHECK-NEXT: # .---command stdout{{-*}}
+#      CHECK: # | @@ {{.*}} @@
+# CHECK-NEXT: # | 4
+# CHECK-NEXT: # | 5
+# CHECK-NEXT: # | -6 foo
+# CHECK-NEXT: # | +6 bar
+# CHECK-NEXT: # | 7
+# CHECK-NEXT: # | 8
+# CHECK-NEXT: # `---{{-*}}
+# CHECK-NEXT: # error: command failed with exit status: 1
+# CHECK-NEXT: # executed command: true
+
+#      CHECK: diff -U4 {{.*}}.foo {{.*}}.bar && false || true
+# CHECK-NEXT: # executed command: diff -U4 {{.+}}.foo{{.*}} {{.+}}.bar{{.*}}
+# CHECK-NEXT: # .---command stdout{{-*}}
+#      CHECK: # | @@ {{.*}} @@
+# CHECK-NEXT: # | 2
+# CHECK-NEXT: # | 3
+# CHECK-NEXT: # | 4
+# CHECK-NEXT: # | 5
+# CHECK-NEXT: # | -6 foo
+# CHECK-NEXT: # | +6 bar
+# CHECK-NEXT: # | 7
+# CHECK-NEXT: # | 8
+# CHECK-NEXT: # | 9
+# CHECK-NEXT: # | 10
+# CHECK-NEXT: # `---{{-*}}
+# CHECK-NEXT: # error: command failed with exit status: 1
+# CHECK-NEXT: # executed command: true
+
+#      CHECK: diff -U0 {{.*}}.foo {{.*}}.bar && false || true
+# CHECK-NEXT: # executed command: diff -U0 {{.+}}.foo{{.*}} {{.+}}.bar{{.*}}
+# CHECK-NEXT: # .---command stdout{{-*}}
+#      CHECK: # | @@ {{.*}} @@
+# CHECK-NEXT: # | -6 foo
+# CHECK-NEXT: # | +6 bar
+# CHECK-NEXT: # `---{{-*}}
+# CHECK-NEXT: # error: command failed with exit status: 1
+# CHECK-NEXT: # executed command: true
+
+# CHECK: diff -U 30.1 {{.*}} {{.*}} && false || true
+# CHECK: # executed command: diff -U 30.1 {{.*}} {{.*}}
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | Error: invalid '-U' argument: 30.1
+# CHECK: # error: command failed with exit status: 1
+# CHECK: # executed command: true
+
+# CHECK: diff -U-1 {{.*}} {{.*}} && false || true
+# CHECK: # executed command: diff -U-1 {{.*}} {{.*}}
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | Error: invalid '-U' argument: -1
+# CHECK: # error: command failed with exit status: 1
+# CHECK: # executed command: true
 
-# CHECK: $ "diff" "-U" "2" "{{[^"]*}}.foo" "{{[^"]*}}.bar"
-# CHECK: # command output:
-# CHECK: @@ {{.*}} @@
-# CHECK-NEXT: 4
-# CHECK-NEXT: 5
-# CHECK-NEXT: -6 foo
-# CHECK-NEXT: +6 bar
-# CHECK-NEXT: 7
-# CHECK-NEXT: 8
-# CHECK-EMPTY:
-# CHECK-NEXT: error: command failed with exit status: 1
-# CHECK-NEXT: $ "true"
-
-# CHECK: $ "diff" "-U4" "{{[^"]*}}.foo" "{{[^"]*}}.bar"
-# CHECK: # command output:
-# CHECK: @@ {{.*}} @@
-# CHECK-NEXT: 2
-# CHECK-NEXT: 3
-# CHECK-NEXT: 4
-# CHECK-NEXT: 5
-# CHECK-NEXT: -6 foo
-# CHECK-NEXT: +6 bar
-# CHECK-NEXT: 7
-# CHECK-NEXT: 8
-# CHECK-NEXT: 9
-# CHECK-NEXT: 10
-# CHECK-EMPTY:
-# CHECK-NEXT: error: command failed with exit status: 1
-# CHECK-NEXT: $ "true"
-
-# CHECK: $ "diff" "-U0" "{{[^"]*}}.foo" "{{[^"]*}}.bar"
-# CHECK: # command output:
-# CHECK: @@ {{.*}} @@
-# CHECK-NEXT: -6 foo
-# CHECK-NEXT: +6 bar
-# CHECK-EMPTY:
-# CHECK-NEXT: error: command failed with exit status: 1
-# CHECK-NEXT: $ "true"
-
-# CHECK: $ "diff" "-U" "30.1" "{{[^"]*}}" "{{[^"]*}}"
-# CHECK: # command stderr:
-# CHECK: Error: invalid '-U' argument: 30.1
-# CHECK: error: command failed with exit status: 1
-# CHECK: $ "true"
-
-# CHECK: $ "diff" "-U-1" "{{[^"]*}}" "{{[^"]*}}"
-# CHECK: # command stderr:
-# CHECK: Error: invalid '-U' argument: -1
-# CHECK: error: command failed with exit status: 1
-# CHECK: $ "true"
-
-# CHECK: $ "false"
+# CHECK: false
 
 # CHECK: ***
 
 
-# CHECK: FAIL: shtest-shell :: diff-w.txt
-# CHECK: *** TEST 'shtest-shell :: diff-w.txt' FAILED ***
-# CHECK: $ "diff" "-w" "{{[^"]*}}.0" "{{[^"]*}}.1"
-# CHECK: # command output:
-# CHECK: 1,3
-# CHECK-NEXT: {{^  }}foo
-# CHECK-NEXT: {{^  }}bar
-# CHECK-NEXT: ! baz
-# CHECK-NEXT: ---
-# CHECK-NEXT: {{^  }}foo
-# CHECK-NEXT: {{^  }}bar
-# CHECK-NEXT: ! bat
-# CHECK-EMPTY:
-# CHECK: error: command failed with exit status: 1
-# CHECK: ***
+#      CHECK: FAIL: shtest-shell :: diff-w.txt
+#      CHECK: *** TEST 'shtest-shell :: diff-w.txt' FAILED ***
+#      CHECK: diff -w {{.*}}.0 {{.*}}.1
+#      CHECK: # .---command stdout{{-*}}
+#      CHECK: # | {{\*+}} 1,3
+# CHECK-NEXT: # |   foo
+# CHECK-NEXT: # |   bar
+# CHECK-NEXT: # | ! baz
+# CHECK-NEXT: # | ---
+# CHECK-NEXT: # |   foo
+# CHECK-NEXT: # |   bar
+# CHECK-NEXT: # | ! bat
+# CHECK-NEXT: # `---{{-*}}
+# CHECK-NEXT: # error: command failed with exit status: 1
+#      CHECK: ***
+
+# CHECK: FAIL: shtest-shell :: echo-at-redirect-stderr.txt
+# CHECK: *** TEST 'shtest-shell :: echo-at-redirect-stderr.txt' FAILED ***
+# CHECK: @echo 2> {{.*}}
+# CHECK: # executed command: @echo
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | stdin and stderr redirects not supported for @echo
+# CHECK: error: command failed with exit status:
+
+# CHECK: FAIL: shtest-shell :: echo-at-redirect-stdin.txt
+# CHECK: *** TEST 'shtest-shell :: echo-at-redirect-stdin.txt' FAILED ***
+# CHECK: @echo < {{.*}}
+# CHECK: # executed command: @echo
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | stdin and stderr redirects not supported for @echo
+# CHECK: error: command failed with exit status:
+
+# CHECK: FAIL: shtest-shell :: echo-redirect-stderr.txt
+# CHECK: *** TEST 'shtest-shell :: echo-redirect-stderr.txt' FAILED ***
+# CHECK: echo 2> {{.*}}
+# CHECK: # executed command: echo
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | stdin and stderr redirects not supported for echo
+# CHECK: error: command failed with exit status:
+
+# CHECK: FAIL: shtest-shell :: echo-redirect-stdin.txt
+# CHECK: *** TEST 'shtest-shell :: echo-redirect-stdin.txt' FAILED ***
+# CHECK: echo < {{.*}}
+# CHECK: # executed command: echo
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | stdin and stderr redirects not supported for echo
+# CHECK: error: command failed with exit status:
 
 # CHECK: FAIL: shtest-shell :: error-0.txt
 # CHECK: *** TEST 'shtest-shell :: error-0.txt' FAILED ***
-# CHECK: $ "not-a-real-command"
-# CHECK: # command stderr:
-# CHECK: 'not-a-real-command': command not found
-# CHECK: error: command failed with exit status: 127
+# CHECK: not-a-real-command
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | 'not-a-real-command': command not found
+# CHECK: # error: command failed with exit status: 127
 # CHECK: ***
 
 # FIXME: The output here sucks.
 #
 # CHECK: FAIL: shtest-shell :: error-1.txt
 # CHECK: *** TEST 'shtest-shell :: error-1.txt' FAILED ***
-# CHECK: shell parser error on: ': \'RUN: at line 3\'; echo "missing quote'
+# CHECK: shell parser error on RUN: at line 3: echo "missing quote
 # CHECK: ***
 
 # CHECK: FAIL: shtest-shell :: error-2.txt
 # CHECK: *** TEST 'shtest-shell :: error-2.txt' FAILED ***
 # CHECK: Unsupported redirect:
 # CHECK: ***
 
 # CHECK: FAIL: shtest-shell :: mkdir-error-0.txt
 # CHECK: *** TEST 'shtest-shell :: mkdir-error-0.txt' FAILED ***
-# CHECK: $ "mkdir" "-p" "temp"
-# CHECK: # command stderr:
-# CHECK: Unsupported: 'mkdir' cannot be part of a pipeline
-# CHECK: error: command failed with exit status: 127
+# CHECK: mkdir -p temp | rm -rf temp
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | Unsupported: 'mkdir' cannot be part of a pipeline
+# CHECK: # error: command failed with exit status: 127
 # CHECK: ***
 
 # CHECK: FAIL: shtest-shell :: mkdir-error-1.txt
 # CHECK: *** TEST 'shtest-shell :: mkdir-error-1.txt' FAILED ***
-# CHECK: $ "mkdir" "-p" "-m" "777" "temp"
-# CHECK: # command stderr:
-# CHECK: Unsupported: 'mkdir': option -m not recognized
-# CHECK: error: command failed with exit status: 127
+# CHECK: mkdir -p -m 777 temp
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | Unsupported: 'mkdir': option -m not recognized
+# CHECK: # error: command failed with exit status: 127
 # CHECK: ***
 
 # CHECK: FAIL: shtest-shell :: mkdir-error-2.txt
 # CHECK: *** TEST 'shtest-shell :: mkdir-error-2.txt' FAILED ***
-# CHECK: $ "mkdir" "-p"
-# CHECK: # command stderr:
-# CHECK: Error: 'mkdir' is missing an operand
-# CHECK: error: command failed with exit status: 127
+# CHECK: mkdir -p
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | Error: 'mkdir' is missing an operand
+# CHECK: # error: command failed with exit status: 127
 # CHECK: ***
 
 # CHECK: PASS: shtest-shell :: redirects.txt
 
 # CHECK: FAIL: shtest-shell :: rm-error-0.txt
 # CHECK: *** TEST 'shtest-shell :: rm-error-0.txt' FAILED ***
-# CHECK: $ "rm" "-rf" "temp"
-# CHECK: # command stderr:
-# CHECK: Unsupported: 'rm' cannot be part of a pipeline
-# CHECK: error: command failed with exit status: 127
+# CHECK: rm -rf temp | echo "hello"
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | Unsupported: 'rm' cannot be part of a pipeline
+# CHECK: # error: command failed with exit status: 127
 # CHECK: ***
 
 # CHECK: FAIL: shtest-shell :: rm-error-1.txt
 # CHECK: *** TEST 'shtest-shell :: rm-error-1.txt' FAILED ***
-# CHECK: $ "rm" "-f" "-v" "temp"
-# CHECK: # command stderr:
-# CHECK: Unsupported: 'rm': option -v not recognized
-# CHECK: error: command failed with exit status: 127
+# CHECK: rm -f -v temp
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | Unsupported: 'rm': option -v not recognized
+# CHECK: # error: command failed with exit status: 127
 # CHECK: ***
 
 # CHECK: FAIL: shtest-shell :: rm-error-2.txt
 # CHECK: *** TEST 'shtest-shell :: rm-error-2.txt' FAILED ***
-# CHECK: $ "rm" "-r" "hello"
-# CHECK: # command stderr:
-# CHECK: Error: 'rm' command failed
-# CHECK: error: command failed with exit status: 1
+# CHECK: rm -r hello
+# CHECK: # .---command stderr{{-*}}
+# CHECK: # | Error: 'rm' command failed
+# CHECK: # error: command failed with exit status: 1
 # CHECK: ***
 
 # CHECK: FAIL: shtest-shell :: rm-error-3.txt
 # CHECK: *** TEST 'shtest-shell :: rm-error-3.txt' FAILED ***
 # CHECK: Exit Code: 1
 # CHECK: ***
 
 # CHECK: PASS: shtest-shell :: rm-unicode-0.txt
 # CHECK: PASS: shtest-shell :: sequencing-0.txt
 # CHECK: XFAIL: shtest-shell :: sequencing-1.txt
 
-# CHECK: FAIL: shtest-shell :: stdout-encoding.txt
-# CHECK: *** TEST 'shtest-shell :: stdout-encoding.txt' FAILED ***
-# CHECK: $ "cat" "diff-in.bin"
-# CHECK: # command output:
-# CHECK-NEXT: {{^.f.o.o.$}}
-# CHECK-NEXT: {{^.b.a.r.}}
-# CHECK-NEXT: {{^.b.a.z.$}}
-# CHECK-NOT: error
-# CHECK: $ "false"
-# CHECK: ***
+#      CHECK: FAIL: shtest-shell :: stdout-encoding.txt
+#      CHECK: *** TEST 'shtest-shell :: stdout-encoding.txt' FAILED ***
+#      CHECK: cat diff-in.bin
+#      CHECK: # .---command stdout{{-*}}
+# CHECK-NEXT: # | {{.f.o.o.$}}
+# CHECK-NEXT: # | {{.b.a.r.}}
+# CHECK-NEXT: # | {{.b.a.z.$}}
+# CHECK-NEXT: # `---{{-*}}
+#  CHECK-NOT: error
+#      CHECK: false
+#      CHECK: ***
 
 # CHECK: PASS: shtest-shell :: valid-shell.txt
-# CHECK: Failed Tests (35)
+# CHECK: Failed Tests (39)