CAT(1)                     OpenBSD Reference Manual                     CAT(1)

NAME
     cat - concatenate and print files



SYNOPSIS
     cat [-benstuv] [file ...]

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:

     -n      Number the output lines, starting at 1.

     -b      Implies the -n option but doesn't number blank lines.

     -v      Displays non-printing characters so they are visible.  Control
             characters print as `^X' for control-X. The only exception is the
             tab character, control-I (see the -t option). 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.

     -e      Implies the -v option and also prints a dollar sign (`$') at the
             end of each line.

     -t      Implies the -v option and also prints tab characters as `^I'.

     -s      Squeeze multiple adjacent empty lines, causing the output to be
             single spaced.

     -u      The -u option guarantees that the output is unbuffered (see
             setbuf(3)).

     The cat utility exits 0 on success or >0 if an error occurred.

EXAMPLES
     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 (i.e., 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 stan-
     dard input until it receives an EOF (`^D') character, print the contents
     of file2, read and output contents of the standard input again, then fi-
     nally output the contents of file3. Note that if the standard input re-
     ferred to a file, the second dash on the command-line would have no ef-
     fect, 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),  less(1),  more(1),  pr(1),  sh(1),  tail(1),  vis(1),  set-
     buf(3)

     Rob Pike, "UNIX Style, or cat -v Considered Harmful", USENIX Summer
     Conference Proceedings, 1983.

STANDARDS
     The cat utility is compliant with the IEEE Std1003.2-1992 (``POSIX.2'')
     specification.

     The flags [-benstv] are extensions to the specification.

HISTORY
     A cat utility appeared in Version 1 AT&T UNIX.

BUGS
     Because of the shell language mechanism used to perform output redirec-
     tion, the command cat file1 file2 > file1 will cause the original data in
     file1 to be destroyed!


OpenBSD 2.6                       May 2, 1995                                2