3.1 cat: Concatenate and write files

cat copies each file (‘-’ means standard input), or standard input if none are given, to standard output. Synopsis:

cat [option] [file]…

The program accepts the following options. Also see Common options.

‘-A’

‘--show-all’

Equivalent to -vET.

‘-b’

‘--number-nonblank’

Number all nonempty output lines, starting with 1.

‘-e’

Equivalent to -vE.

‘-E’

‘--show-ends’

Display a ‘$’ after the end of each line.

‘-n’

‘--number’

Number all output lines, starting with 1. This option is ignored if -b is in effect.

‘-s’

‘--squeeze-blank’

Suppress repeated adjacent blank lines; output just one empty line instead of several.

‘-t’

Equivalent to -vT.

‘-T’

‘--show-tabs’

Display TAB characters as ‘^I’.

‘-u’

Ignored; for POSIX compatibility.

‘-v’

‘--show-nonprinting’

Display control characters except for LFD and TAB using ‘^’ notation and precede characters that have the high bit set with ‘M-’.

On systems like MS-DOS that distinguish between text and binary files, cat normally reads and writes in binary mode. However, cat reads in text mode if one of the options -bensAE is used or if cat is reading from standard input and standard input is a terminal. Similarly, cat writes in text mode if one of the options -bensAE is used or if standard output is a terminal.

An exit status of zero indicates success, and a nonzero value indicates failure.

Examples:

# Output f's contents, then standard input, then g's contents.
cat f - g

# Copy standard input to standard output.
cat