1.\" Copyright (c) 1980, 1990, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the Institute of Electrical and Electronics Engineers, Inc. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. All advertising materials mentioning features or use of this software 16.\" must display the following acknowledgement: 17.\" This product includes software developed by the University of 18.\" California, Berkeley and its contributors. 19.\" 4. Neither the name of the University nor the names of its contributors 20.\" may be used to endorse or promote products derived from this software 21.\" without specific prior written permission. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33.\" SUCH DAMAGE. 34.\" 35.\" @(#)tail.1 8.1 (Berkeley) 6/6/93 36.\" $FreeBSD: src/usr.bin/tail/tail.1,v 1.5.2.4 2002/07/15 07:46:27 keramida Exp $ 37.\" $DragonFly: src/usr.bin/tail/tail.1,v 1.3 2007/07/30 22:11:33 swildner Exp $ 38.\" 39.Dd June 6, 1993 40.Dt TAIL 1 41.Os 42.Sh NAME 43.Nm tail 44.Nd display the last part of a file 45.Sh SYNOPSIS 46.Nm 47.Oo 48.Fl F | 49.Fl f | 50.Fl r 51.Oc 52.Oo 53.Fl b Ar number | 54.Fl c Ar number | 55.Fl n Ar number 56.Oc 57.Op Ar 58.Sh DESCRIPTION 59The 60.Nm 61utility displays the contents of 62.Ar file 63or, by default, its standard input, to the standard output. 64.Pp 65The display begins at a byte, line or 512-byte block location in the 66input. 67Numbers having a leading plus (``+'') sign are relative to the beginning 68of the input, for example, 69.Dq -c +2 70starts the display at the second 71byte of the input. 72Numbers having a leading minus (``-'') sign or no explicit sign are 73relative to the end of the input, for example, 74.Dq -n 2 75displays the last two lines of the input. 76The default starting location is 77.Dq -n 10 , 78or the last 10 lines of the input. 79.Pp 80The options are as follows: 81.Bl -tag -width Ds 82.It Fl b Ar number 83The location is 84.Ar number 85512-byte blocks. 86.It Fl c Ar number 87The location is 88.Ar number 89bytes. 90.It Fl f 91The 92.Fl f 93option causes 94.Nm 95to not stop when end of file is reached, but rather to wait for additional 96data to be appended to the input. 97The 98.Fl f 99option is ignored if the standard input is a pipe, but not if it is a FIFO. 100.It Fl F 101The 102.Fl F 103option implies the 104.Fl f 105option, but 106.Nm 107will also check to see if the file being followed has been renamed or rotated. 108The file is closed and reopened when 109.Nm 110detects that the filename being read from has a new inode number. 111The 112.Fl F 113option is ignored if reading from standard input rather than a file. 114.It Fl n Ar number 115The location is 116.Ar number 117lines. 118.It Fl r 119The 120.Fl r 121option causes the input to be displayed in reverse order, by line. 122Additionally, this option changes the meaning of the 123.Fl b , 124.Fl c 125and 126.Fl n 127options. 128When the 129.Fl r 130option is specified, these options specify the number of bytes, lines 131or 512-byte blocks to display, instead of the bytes, lines or blocks 132from the beginning or end of the input from which to begin the display. 133The default for the 134.Fl r 135option is to display all of the input. 136.El 137.Pp 138If more than a single file is specified, each file is preceded by a 139header consisting of the string 140.Dq ==> XXX <== 141where 142.Dq XXX 143is the name of the file. 144.Sh EXIT STATUS 145.Ex -std 146.Sh SEE ALSO 147.Xr cat 1 , 148.Xr head 1 , 149.Xr sed 1 150.Sh STANDARDS 151The 152.Nm 153utility is expected to be a superset of the 154.St -p1003.2-92 155specification. 156In particular, the 157.Fl F , 158.Fl b 159and 160.Fl r 161options are extensions to that standard. 162.Pp 163The historic command line syntax of 164.Nm 165is supported by this implementation. 166The only difference between this implementation and historic versions 167of 168.Nm , 169once the command line syntax translation has been done, is that the 170.Fl b , 171.Fl c 172and 173.Fl n 174options modify the 175.Fl r 176option, i.e. ``-r -c 4'' displays the last 4 characters of the last line 177of the input, while the historic tail (using the historic syntax ``-4cr'') 178would ignore the 179.Fl c 180option and display the last 4 lines of the input. 181.Sh HISTORY 182A 183.Nm 184command appeared in PWB 185.Ux . 186