CAT(1) - General Commands Manual #
CAT(1) - General Commands Manual
NAME #
cat - concatenate and print files
SYNOPSIS #
cat [-benstuv] [fileĀ …]
DESCRIPTION #
The cat utility reads files sequentially, writing them to the standard output. The file operands are processed in command-line order. If file is a single dash (’-’) or absent, cat reads from the standard input.
The options are as follows:
-b
Number the lines, but don’t count blank lines.
-e
Print a dollar sign (’
$
’) at the end of each line. Implies the -v option to display non-printing characters.
-n
Number the output lines, starting at 1.
-s
Squeeze multiple adjacent empty lines, causing the output to be
single spaced.
-t
Print tab characters as
'`^I`'.
Implies the
**-v**
option to display non-printing characters.
-u
The output is guaranteed to be unbuffered (see
[setvbuf(3)](/man/man3/setvbuf.3)).
-v
Displays non-printing characters so they are visible.
Control characters print as
'`^X`'
for control-X, with the exception of the tab and EOL characters,
which are displayed normally.
The DEL character (octal 0177) prints as
'`^?`'.
Non-ASCII characters (with the high bit set) are printed as
'`M-`'
(for meta) followed by the character for the low 7 bits.
EXIT STATUS #
The cat utility exits0 on success, and>0 if an error occurs.
EXAMPLES #
Print the contents of file1 to the standard output:
$ cat file1
Sequentially print the contents of file1 and file2 to the file file3, truncating file3 if it already exists. See the manual page for your shell (e.g., sh(1)) for more information on redirection.
$ cat file1 file2 > file3
Print the contents of
file1,
print data it receives from the standard input until it receives an
EOF
(’^D’)
character, print the contents of
file2,
read and output contents of the standard input again, then finally output
the contents of
file3.
Note that if the standard input referred to a file, the second dash
on the command line would have no effect, since the entire contents of the file
would have already been read and printed by
cat
when it encountered the first
‘-
’
operand.
$ cat file1 - file2 - file3
SEE ALSO #
head(1), less(1), more(1), pr(1), sh(1), tail(1), vis(1), setvbuf(3)
Rob Pike, “UNIX Style, or cat -v Considered Harmful”, USENIX Summer Conference Proceedings, 1983.
STANDARDS #
The cat utility is compliant with the IEEE Std 1003.1-2008 (“POSIX.1”) specification.
The flags [-benstv] are extensions to that specification.
HISTORY #
A cat utility appeared in Version1 AT&T UNIX.
CAVEATS #
Because of the shell language mechanism used to perform output redirection, the following command will cause the original data in file1 to be destroyed:
$ cat file1 file2 > file1
To append file2 to file1, instead use:
$ cat file2 » file1
OpenBSD 7.5 - July 10, 2016