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.\" 4. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" @(#)tail.1 8.1 (Berkeley) 6/6/93 32.\" $FreeBSD: src/usr.bin/tail/tail.1,v 1.5.2.4 2002/07/15 07:46:27 keramida Exp $ 33.\" $DragonFly: src/usr.bin/tail/tail.1,v 1.3 2007/07/30 22:11:33 swildner Exp $ 34.\" 35.Dd June 6, 1993 36.Dt TAIL 1 37.Os 38.Sh NAME 39.Nm tail 40.Nd display the last part of a file 41.Sh SYNOPSIS 42.Nm 43.Oo 44.Fl F | 45.Fl f | 46.Fl r 47.Oc 48.Oo 49.Fl b Ar number | 50.Fl c Ar number | 51.Fl n Ar number 52.Oc 53.Op Ar 54.Sh DESCRIPTION 55The 56.Nm 57utility displays the contents of 58.Ar file 59or, by default, its standard input, to the standard output. 60.Pp 61The display begins at a byte, line or 512-byte block location in the 62input. 63Numbers having a leading plus (``+'') sign are relative to the beginning 64of the input, for example, 65.Dq -c +2 66starts the display at the second 67byte of the input. 68Numbers having a leading minus (``-'') sign or no explicit sign are 69relative to the end of the input, for example, 70.Dq -n 2 71displays the last two lines of the input. 72The default starting location is 73.Dq -n 10 , 74or the last 10 lines of the input. 75.Pp 76The options are as follows: 77.Bl -tag -width Ds 78.It Fl b Ar number 79The location is 80.Ar number 81512-byte blocks. 82.It Fl c Ar number 83The location is 84.Ar number 85bytes. 86.It Fl f 87The 88.Fl f 89option causes 90.Nm 91to not stop when end of file is reached, but rather to wait for additional 92data to be appended to the input. 93The 94.Fl f 95option is ignored if the standard input is a pipe, but not if it is a FIFO. 96.It Fl F 97The 98.Fl F 99option implies the 100.Fl f 101option, but 102.Nm 103will also check to see if the file being followed has been renamed or rotated. 104The file is closed and reopened when 105.Nm 106detects that the filename being read from has a new inode number. 107The 108.Fl F 109option is ignored if reading from standard input rather than a file. 110.It Fl n Ar number 111The location is 112.Ar number 113lines. 114.It Fl r 115The 116.Fl r 117option causes the input to be displayed in reverse order, by line. 118Additionally, this option changes the meaning of the 119.Fl b , 120.Fl c 121and 122.Fl n 123options. 124When the 125.Fl r 126option is specified, these options specify the number of bytes, lines 127or 512-byte blocks to display, instead of the bytes, lines or blocks 128from the beginning or end of the input from which to begin the display. 129The default for the 130.Fl r 131option is to display all of the input. 132.El 133.Pp 134If more than a single file is specified, each file is preceded by a 135header consisting of the string 136.Dq ==> XXX <== 137where 138.Dq XXX 139is the name of the file. 140.Sh EXIT STATUS 141.Ex -std 142.Sh SEE ALSO 143.Xr cat 1 , 144.Xr head 1 , 145.Xr sed 1 146.Sh STANDARDS 147The 148.Nm 149utility is expected to be a superset of the 150.St -p1003.2-92 151specification. 152In particular, the 153.Fl F , 154.Fl b 155and 156.Fl r 157options are extensions to that standard. 158.Pp 159The historic command line syntax of 160.Nm 161is supported by this implementation. 162The only difference between this implementation and historic versions 163of 164.Nm , 165once the command line syntax translation has been done, is that the 166.Fl b , 167.Fl c 168and 169.Fl n 170options modify the 171.Fl r 172option, i.e. ``-r -c 4'' displays the last 4 characters of the last line 173of the input, while the historic tail (using the historic syntax ``-4cr'') 174would ignore the 175.Fl c 176option and display the last 4 lines of the input. 177.Sh HISTORY 178A 179.Nm 180command appeared in PWB 181.Ux . 182