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TAIL(1)			  BSD General Commands Manual		       TAIL(1)

     tail -- display the last part of a	file

     tail [-f |	-F | -r] [-b number | -c number	| -n number] [file ...]

     The tail utility displays the contents of file or,	by default, its	stan-
     dard input, to the	standard output.

     The display begins	at a byte, line	or 512-byte block location in the in-
     put.  Numbers having a leading plus (``+'') sign are relative to the be-
     ginning of	the input, for example,	"-c +2"	starts the display at the sec-
     ond byte of the input.  Numbers having a leading minus (``-'') sign or no
     explicit sign are relative	to the end of the input, for example, "-n 2"
     displays the last two lines of the	input.	The default starting location
     is	"-n 10", or the	last 10	lines of the input.

     The options are as	follows:

     -b	number
	     The location is number 512-byte blocks.

     -c	number
	     The location is number bytes.

     -f	     The -f option causes tail to not stop when	end of file is
	     reached, but rather to wait for additional	data to	be appended to
	     the input.	 The -f	option is ignored if the standard input	is a
	     pipe, but not if it is a FIFO.

     -F	     The -F option is the same as the -f option, except	that every
	     five seconds tail will check to see if the	file named on the com-
	     mand line has been	shortened or moved (it is considered moved if
	     the inode or device number	changes) and, if so, it	will close the
	     current file, open	the filename given, print out the entire con-
	     tents, and	continue to wait for more data to be appended.	This
	     option is used to follow log files	though rotation	by
	     newsyslog(8) or similar programs.

     -n	number
	     The location is number lines.

     -r	     The -r option causes the input to be displayed in reverse order,
	     by	line.  Additionally, this option changes the meaning of	the
	     -b, -c and	-n options.  When the -r option	is specified, these
	     options specify the number	of bytes, lines	or 512-byte blocks to
	     display, instead of the bytes, lines or blocks from the beginning
	     or	end of the input from which to begin the display.  The default
	     for the -r	option is to display all of the	input.

     If	more than a single file	is specified, each file	is preceded by a
     header consisting of the string "==> XXX <==" where "XXX" is the name of
     the file.

     The tail utility exits 0 on success, and >0 if an error occurs.

     cat(1), head(1), sed(1)

     The tail utility is expected to be	a superset of the IEEE Std 1003.2-1992
     ("POSIX.2") specification.	 In particular,	the -b,	-r and -F options are
     extensions	to that	standard.

     The historic command line syntax of tail is supported by this implementa-
     tion.  The	only difference	between	this implementation and	historic ver-
     sions of tail, once the command line syntax translation has been done, is
     that the -b, -c and -n options modify the -r option, i.e. ``-r -c 4''
     displays the last 4 characters of the last	line of	the input, while the
     historic tail (using the historic syntax ``-4cr'')	would ignore the -c
     option and	display	the last 4 lines of the	input.

     A tail command appeared in	Version	7 AT&T UNIX.

     When using	the -F option, tail will not detect a file truncation if, be-
     tween the truncation and the next check of	the file size, data written to
     the file make it larger than the last known file size.

BSD				 June 6, 1993				   BSD


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