cat(1) - NetBSD Manual Pages

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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 3.0                        May 2, 1995                       NetBSD 3.0