Cmp (Unix)

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cmp is a command line utility for computer systems that use a Unix operating system. It compares two files of any type and writes the results to the standard output. By default, cmp is silent if the files are the same; if they differ, the byte and line number at which the first difference occurred is reported.

Switches

cmp may be qualified by the use of the following switches, (the long versions are in brackets):

• -b (--print-bytes) - Print differing bytes.
• -i SKIP (--ignore-initial=SKIP) - Skip the first SKIP bytes of input.
• -i SKIP1:SKIP2 (--ignore-initial=SKIP1:SKIP2) - Skip the first SKIP1 bytes of FILE1 and the first SKIP2 bytes of FILE2.
• -l (--verbose) - Output byte numbers and values of all differing bytes.
• -n LIMIT (--bytes=LIMIT) - Compare at most LIMIT bytes.
• -s (--quiet --silent) - Output nothing; yield exit status only.
• -v (--version) - Output version info.
• --help - Outputs a help file.

Return values

• 0 - files are identical
• 1 - files differ
• 2 - inaccessible or missing argument

See also

• Comparison of file comparison tools
• List of Unix programs

External links

• Comparing and Merging Files: Invoking cmp The section of the manual of GNU cmp in the diffutils free manual.