Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages


home | help
CAT(1)			  BSD General Commands Manual			CAT(1)

     cat -- concatenate	and print files

     cat [-beflnstuv] [-] [file	...]

     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	de-
	     scriptor.	This lock is set using fcntl(2)	with the F_SETLKW com-
	     mand.  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

     -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 (oc-
	     tal 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	(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.

     head(1), hexdump(1), lpr(1), more(1), pr(1), tail(1), view(1), vis(1),

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

     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.

     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 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

BSD			      September	23, 2006			   BSD


Want to link to this manual page? Use this URL:

home | help