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CMP

Posted On 2007-04-27 by FortyPoundHead
Keywords: Command Reference
Tags: Linux Commandline Linux
Views: 1464


Compare two files, and if they differ, tells the first byte and line number where they differ.

You can use the `cmp'' command to show the offsets and line numbers where two files differ. `cmp'' can also show all the characters that differ between the two files, side by side.


SYNTAX
cmp options... FromFile [ToFile]

OPTIONS
Multiple single letter options (unless they take an argument)
can be combined into a single command line word:
so `-cl'' is equivalent to `-c -l''.

`-c''
Print the differing characters. Display control characters as a
`^'' followed by a letter of the alphabet and precede characters
that have the high bit set with `M-'' (which stands for "meta").

`--ignore-initial=BYTES''
Ignore any differences in the the first BYTES bytes of the input
files. Treat files with fewer than BYTES bytes as if they are
empty.

`-l''
Print the (decimal) offsets and (octal) values of all differing
bytes.

`--print-chars''
Print the differing characters. Display control characters as a
`^'' followed by a letter of the alphabet and precede characters
that have the high bit set with `M-'' (which stands for "meta").

`--quiet''
`-s''
`--silent''
Do not print anything; only return an exit status indicating
whether the files differ.

`--verbose''
Print the (decimal) offsets and (octal) values of all differing
bytes.

`-v''
`--version''
Output the version number of `cmp''.

The file name `-'' is always the standard input. `cmp'' also uses the
standard input if one file name is omitted.

An exit status of 0 means no differences were found, 1 means some
differences were found, and 2 means trouble.
Example

$ cmp tnsnames.ora tnsnames.old

Notes
`cmp'' reports the differences between two files character by character, instead of line by line. As a result, it is more useful than `diff'' for comparing binary files. For text files, `cmp'' is useful mainly when you want to know only whether two files are identical.

For files that are identical, `cmp'' produces no output. When the files differ, by default, `cmp'' outputs the byte offset and line number where the first difference occurs. You can use the `-s'' option to suppress that information, so that `cmp'' produces no output and reports whether the files differ using only its exit status.
Unlike `diff'', `cmp'' cannot compare directories; it can only compare two files.


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