cat(1)
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CAT(1) NetBSD General Commands Manual CAT(1)
NAME
cat - concatenate and print files
SYNOPSIS
cat [-beflnstuv] [-] [file ...]
DESCRIPTION
The cat utility reads files sequentially, writing them to the standard
output. The file operands are processed in command line order. A single
dash represents the standard input, and may appear multiple times in the
file list.
The word ``concatenate'' is just a verbose synonym for ``catenate''.
The options are as follows:
-b Implies the -n option but doesn't number blank lines.
-e Implies the -v option, and displays a dollar sign (`$') at the
end of each line as well.
-f Only attempt to display regular files.
-l Set an exclusive advisory lock on the standard output file
descriptor. This lock is set using fcntl(2) with the F_SETLKW
command. If the output file is already locked, cat will block
until the lock is acquired.
-n Number the output lines, starting at 1.
-s Squeeze multiple adjacent empty lines, causing the output to be
single spaced.
-t Implies the -v option, and displays tab characters as `^I' as
well.
-u The -u option guarantees that the output is unbuffered.
-v Displays 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.
EXIT STATUS
The cat utility exits 0 on success, and >0 if an error occurs.
SEE ALSO
head(1), hexdump(1), lpr(1), more(1), pr(1), tail(1), view(1), vis(1),
fcntl(2)
Rob Pike, "UNIX Style, or cat -v Considered Harmful", USENIX Summer
Conference Proceedings, 1983.
STANDARDS
The cat utility is expected to conform to the IEEE Std 1003.2-1992
(``POSIX.2'') specification.
The flags [-belnstv] are extensions to the specification.
HISTORY
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).
BUGS
Because of the shell language mechanism used to perform output redirect-
ion, the command ``cat file1 file2 > file1'' will cause the original data
in file1 to be destroyed! This is performed by the shell before cat is
run.
NetBSD 2.0.2 May 2, 1995 NetBSD 2.0.2
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