cmp

- compare two files

Synopsis

/usr/bin/cmp

/usr/bin/cmp [options] file1 file2 [skip1] [skip2]

ksh93

cmp [options] file1 file2 [skip1] [skip2]

Description

cmp compares two files file1 and file2. cmp writes no output if the files are the same. By default, if the files differ, the byte and line number at which the first difference occurred are written to standard output. Bytes and lines are numbered beginning with 1.

If skip1 or skip2 are specified, or the -i option is specified, initial bytes of the corresponding file are skipped before beginning the compare. The skip values are in bytes or can have a suffix of k for kilobytes or m for megabytes.

If either file1 or files2 is -, cmp uses standard input starting at the current location.

Options

The following options are supported:

-c

--print-chars

Set default skip values for the operands skip1 and skip2 to skip. The default value is 0.

-i

--ignore-inital-skip

Set default skip values for the operands skip1 and skip2 to skip. The default value is 0.

-l

--verbose

Write the decimal byte number and the differing bytes (in octal) for each difference.

-s

--quiet|silent

Write nothing for differing files. Return non-zero exit status only.

-man

--html

--nroff

Print built-in manual page in either plain text, HTML or nroff format.

--help

Print basic help information

--version

Print version information

Operands

The following operands are supported:

file1

A path name of the first file to be compared. If file1 is -, the standard input is used.

file2

A path name of the second file to be compared. If file2 is -, the standard input is used.

If both file1 and file2 refer to standard input or refer to the same FIFO special, block special or character special file, an error results.

Usage

See largefile(5) for the description of the behavior of cmp when encountering files greater than or equal to 2 Gbyte (2³¹ bytes).

Examples

Example 1 Comparing Files Byte for Byte

The following example does a byte for byte comparison of file1 and file2:

example% cmp file1 file2 0 1024

It skips the first 1024 bytes in file2 before starting the comparison.

Environment Variables

See environ(5) for descriptions of the following environment variables that affect the execution of cmp: LANG, LC_ALL, LC_CTYPE, LC_MESSAGES, and NLSPATH.

Exit Status

The following error values are returned:

0

The files are identical.

1

The files are different. This includes the case where one file is identical to the first part of the other.

>1

An error occurred.

Attributes

See attributes(5) for descriptions of the following attributes:

See Also

comm(1), diff(1), ksh93(1), attributes(5), environ(5), largefile(5), standards(5)