CAT(1) | General Commands Manual | CAT(1) |
cat
— concatenate
and print files
cat |
[-belnstuv ] [file
...] |
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. If
file is a UNIX domain socket,
cat
connects to it and then reads it until
EOF
. This complements the
UNIX domain binding capability available in
inetd(8).
The options are as follows:
-b
-e
-v
option), and display a dollar sign
(‘$
’) at the end of each line.-l
F_SETLKW
command. If the output file is
already locked, cat
will block until the lock is
acquired.-n
-s
-t
-v
option), and display tab characters as
‘^I
’.-u
-v
^X
’ for control-X; the
delete 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.The cat
utility exits 0 on success,
and >0 if an error occurs.
The command:
cat file1
will print the contents of file1 to the standard output.
The command:
cat file1 file2 >
file3
will 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.
The command:
cat file1 - file2 -
file3
will 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.
head(1), more(1), pr(1), sh(1), tail(1), vis(1), zcat(1), fcntl(2), setbuf(3)
Rob Pike, UNIX Style, or cat -v Considered Harmful, USENIX Summer Conference Proceedings, 1983.
The cat
utility is compliant with the
IEEE Std 1003.2-1992 (“POSIX.2”)
specification.
The flags [-belnstv
] are extensions to the
specification.
A cat
utility appeared in
Version 1 AT&T UNIX.
Dennis Ritchie designed and wrote the first man
page. It appears to have been for cat
.
Because of the shell language mechanism used to perform output
redirection, the command “cat file1 file2 >
file1
” will cause the original data in
file1 to be destroyed!
The cat
utility does not recognize
multibyte characters when the -t
or
-v
option is in effect.
January 29, 2013 | macOS 14.6 |