Index: utils/lit/lit/TestRunner.py
===================================================================
--- utils/lit/lit/TestRunner.py
+++ utils/lit/lit/TestRunner.py
@@ -558,6 +558,43 @@
             exitCode = 1
     return ShellCommandResult(cmd, "", stderr.getvalue(), exitCode, False)
 
+def executeBuiltinCat(cmd, cmd_shenv):
+    """
+       executeBuiltinCat - Prints contents of a file or merge and print
+       contents of several files.
+    """
+    opened_files = []
+    stdin, stdout, stderr = processRedirects(cmd, subprocess.PIPE, cmd_shenv,
+                                             opened_files)
+    if stdin != subprocess.PIPE or stderr != subprocess.PIPE:
+        raise InternalShellError(
+                cmd, "stdin and stderr redirects not supported for cat")
+
+    isRedirected = True
+    if stdout == subprocess.PIPE:
+        stdout = StringIO()
+        isRedirected = False
+
+    args = expand_glob_expressions(cmd.args, cmd_shenv.cwd)[1:]
+    exitCode = 0
+    errMsg = ""
+    try:
+        for filename in args:
+            fileToCat = open(filename,"r")
+            stdout.write(fileToCat.read())
+            fileToCat.close();
+    except IOError as error:
+        exitCode = 1
+        errMsg = str(error);
+
+    for (name, mode, f, path) in opened_files:
+        f.close()
+
+    contents = "";
+    if (isRedirected == False):
+        contents = stdout.getvalue();
+    return ShellCommandResult(cmd, contents, errMsg, exitCode, False)
+
 def processRedirects(cmd, stdin_source, cmd_shenv, opened_files):
     """Return the standard fds for cmd after applying redirects
 
@@ -740,6 +777,14 @@
         results.append(cmdResult)
         return cmdResult.exitCode
 
+    if cmd.commands[0].args[0] == 'cat':
+        if len(cmd.commands) != 1:
+            raise InternalShellError(cmd.commands[0], "Unsupported: 'cat' "
+                                     "cannot be part of a pipeline")
+        cmdResult = executeBuiltinCat(cmd.commands[0], shenv)
+        results.append(cmdResult)
+        return cmdResult.exitCode
+
     procs = []
     default_stdin = subprocess.PIPE
     stderrTempFiles = []
Index: utils/lit/tests/Inputs/shtest-shell/cat-error-0.txt
===================================================================
--- utils/lit/tests/Inputs/shtest-shell/cat-error-0.txt
+++ utils/lit/tests/Inputs/shtest-shell/cat-error-0.txt
@@ -0,0 +1,3 @@
+# Check error on a unsupported cat (cannot be part of a pipeline).
+#
+# RUN: cat cat-error-0.txt | echo Output
Index: utils/lit/tests/Inputs/shtest-shell/cat-error-1.txt
===================================================================
--- utils/lit/tests/Inputs/shtest-shell/cat-error-1.txt
+++ utils/lit/tests/Inputs/shtest-shell/cat-error-1.txt
@@ -0,0 +1,3 @@
+# Check error on a unsupported cat (Unable to find input file).
+#
+# RUN: cat temp1.txt
Index: utils/lit/tests/Inputs/shtest-shell/valid-shell.txt
===================================================================
--- utils/lit/tests/Inputs/shtest-shell/valid-shell.txt
+++ utils/lit/tests/Inputs/shtest-shell/valid-shell.txt
@@ -85,3 +85,31 @@
 # RUN: cd %T/dir1 && echo "hello" > temp1.txt
 # RUN: cd %T/dir2 && echo "hello" > temp2.txt
 # RUN: diff temp2.txt ../dir1/temp1.txt
+#
+# Check cat command with single file.
+#
+# RUN: rm -rf %T/testCat
+# RUN: mkdir -p %T/testCat
+# RUN: echo "abcdefgh" > %T/testCat/temp.write
+# RUN: cat %T/testCat/temp.write > %T/testCat/tempcat.write
+# RUN: "%{python}" %S/check_path.py file %T/testCat/tempcat.write > %T/testCat/path.out
+# RUN: FileCheck --check-prefix=FILE-EXISTS < %T/testCat/path.out %s
+# RUN: FileCheck --check-prefix=CAT_OUTPUT < %T/testCat/tempcat.write %s
+# FILE-EXISTS: True
+# CAT_OUTPUT: abcdefgh
+#
+# Check cat command with multiple files.
+#
+# RUN: rm -rf %T/testCat
+# RUN: mkdir -p %T/testCat
+# RUN: echo "abcdefgh" > %T/testCat/temp1.write
+# RUN: echo "efghijkl" > %T/testCat/temp2.write
+# RUN: echo "mnopqrst" > %T/testCat/temp3.write
+# RUN: cat %T/testCat/temp1.write %T/testCat/temp2.write %T/testCat/temp3.write > %T/testCat/tempmulticat.write
+# RUN: "%{python}" %S/check_path.py file %T/testCat/tempmulticat.write > %T/testCat/path.out
+# RUN: FileCheck --check-prefix=MULTI-FILE-EXISTS < %T/testCat/path.out %s
+# RUN: FileCheck --check-prefix=MULTI-CAT_OUTPUT < %T/testCat/tempmulticat.write %s
+# MULTI-FILE-EXISTS: True
+# MULTI-CAT_OUTPUT: abcdefgh
+# MULTI-CAT_OUTPUT-NEXT: efghijkl
+# MULTI-CAT_OUTPUT-NEXT: mnopqrst
Index: utils/lit/tests/max-failures.py
===================================================================
--- utils/lit/tests/max-failures.py
+++ utils/lit/tests/max-failures.py
@@ -8,7 +8,7 @@
 #
 # END.
 
-# CHECK: Failing Tests (24)
+# CHECK: Failing Tests (26)
 # CHECK: Failing Tests (1)
 # CHECK: Failing Tests (2)
 # CHECK: error: Setting --max-failures to 0 does not have any effect.
Index: utils/lit/tests/shtest-shell.py
===================================================================
--- utils/lit/tests/shtest-shell.py
+++ utils/lit/tests/shtest-shell.py
@@ -10,6 +10,21 @@
 
 # CHECK: -- Testing:
 
+# CHECK: FAIL: shtest-shell :: cat-error-0.txt
+# CHECK: *** TEST 'shtest-shell :: cat-error-0.txt' FAILED ***
+# CHECK: $ "cat" "cat-error-0.txt"
+# CHECK: # command stderr:
+# CHECK: Unsupported: 'cat' cannot be part of a pipeline
+# CHECK: error: command failed with exit status: 127
+# 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: ***
 
 # CHECK: FAIL: shtest-shell :: diff-error-0.txt
 # CHECK: *** TEST 'shtest-shell :: diff-error-0.txt' FAILED ***
@@ -204,4 +219,4 @@
 # CHECK: PASS: shtest-shell :: sequencing-0.txt
 # CHECK: XFAIL: shtest-shell :: sequencing-1.txt
 # CHECK: PASS: shtest-shell :: valid-shell.txt
-# CHECK: Failing Tests (24)
+# CHECK: Failing Tests (26)