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.


Equivalent to -vET.


Number all nonempty output lines, starting with 1.


Equivalent to -vE.


Display a ‘$’ after the end of each line. The \r\n combination is shown as ‘^M$’.


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


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


Equivalent to -vT.


Display TAB characters as ‘^I’.


Ignored; for POSIX compatibility.


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.


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

# Copy standard input to standard output.