diff --git a/HashProgramOutput.sh b/HashProgramOutput.sh
--- a/HashProgramOutput.sh
+++ b/HashProgramOutput.sh
@@ -6,18 +6,24 @@
 fi
 
 md5cmd=$(which md5sum)
-is_md5sum=1
+is_md5=0
 if [ ! -x "$md5cmd" ]; then
     md5cmd=$(which md5)
-    is_md5sum=0
-    if [ ! -x "$md5cmd" ]; then
-        echo "error: unable to find either 'md5sum' or 'md5'"
-        exit 1
+    if [ -x "$md5cmd" ]; then
+        is_md5=1
+    else
+        md5cmd=$(which csum)
+        if [ ! -x "$md5cmd" ]; then
+            echo "error: unable to find either 'md5sum', 'md5' or 'csum'"
+            exit 1
+        fi
+        # Pass options to make csum behave identically to md5sum.
+        md5cmd="${md5cmd} -h MD5 -"
     fi
 fi
 
 mv $1 $1.bak
-if [ $is_md5sum = "0" ]; then
+if [ $is_md5 = "1" ]; then
     $md5cmd -q < $1.bak > $1
 else
     $md5cmd < $1.bak | cut -d' ' -f 1 > $1