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

     tail -- display the last part of a	file

     tail [-F |	-f | -r] [-q] [-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	begin-
     ning of the input,	for example, "-c +2" starts the	display	at the second
     byte of the input.	 Numbers having	a leading minus	(`-') sign or no ex-
     plicit 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,	--blocks=number
	     The location is number 512-byte blocks.

     -c	number,	--bytes=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 implies the -f option, but tail will	also check to
	     see if the	file being followed has	been renamed or	rotated.  The
	     file is closed and	reopened when tail detects that	the filename
	     being read	from has a new inode number.

	     If	the file being followed	does not (yet) exist or	if it is re-
	     moved, tail will keep looking and will display the	file from the
	     beginning if and when it is created.

	     The -F option is the same as the -f option	if reading from	stan-
	     dard input	rather than a file.

     -n	number,	--lines=number
	     The location is number lines.

     -q	     Suppresses	printing of headers when multiple files	are being ex-

     -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 unless -q	flag is	specified.

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

     To	display	the last 500 lines of the file foo:

	   $ tail -n 500 foo

     Keep /var/log/messages open, displaying to	the standard output anything
     appended to the file:

	   $ tail -F /var/log/messages

     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 -F,	-b and -r 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" dis-
     plays the last 4 characters of the	last line of the input,	while the his-
     toric 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	PWB UNIX.

BSD				March 22, 2020				   BSD


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