CAT(1) General Commands Manual CAT(1)NAME
cat - catenate and print
cat [ -u ] file ...
Cat reads each file in sequence and writes it on the standard output. Thus
prints the file and
cat file1 file2 >file3
concatenates the first two files and places the result on the third.
If no file is given, or if the argument `-' is encountered, cat reads from the standard input. Output is buffered in 512-byte blocks
unless the standard output is a terminal or the -u option is present.
SEE ALSO pr(1), cp(1)BUGS
Beware of `cat a b >a' and `cat a b >b', which destroy input files before reading them.
Check Out this Related Man Page
CAT(1) BSD General Commands Manual CAT(1)NAME
cat -- concatenate and print files
cat [-benstuv] [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 Number the non-blank output lines, starting at 1.
-e Display non-printing characters (see the -v option), and display a dollar sign ('$') at the end of each line.
-n Number the output lines, starting at 1.
-s Squeeze multiple adjacent empty lines, causing the output to be single spaced.
-t Display non-printing characters (see the -v option), and display tab characters as '^I'.
-u The -u option guarantees that the output is unbuffered.
-v Display non-printing characters so they are visible. Control characters print as '^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.
will print the contents of file1 to the standard output.
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 (i.e., sh(1)) for more information on redirection.
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 con-
tents 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.
SEE ALSO head(1), more(1), pr(1), sh(1), tail(1), vis(1), zcat(1), 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 [-benstv] 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 cat(1).
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!
BSD September 15, 2001 BSD