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.\" $FreeBSD$ 37.\" 38.Dd June 29, 2006 39.Dt TAIL 1 40.Os 41.Sh NAME 42.Nm tail 43.Nd display the last part of a file 44.Sh SYNOPSIS 45.Nm 46.Op Fl F | f | r 47.Op Fl q 48.Oo 49.Fl b Ar number | Fl c Ar number | Fl n Ar number 50.Oc 51.Op Ar 52.Sh DESCRIPTION 53The 54.Nm 55utility displays the contents of 56.Ar file 57or, by default, its standard input, to the standard output. 58.Pp 59The display begins at a byte, line or 512-byte block location in the 60input. 61Numbers having a leading plus 62.Pq Ql + 63sign are relative to the beginning 64of the input, for example, 65.Dq Li "-c +2" 66starts the display at the second 67byte of the input. 68Numbers having a leading minus 69.Pq Ql - 70sign or no explicit sign are 71relative to the end of the input, for example, 72.Dq Li "-n 2" 73displays the last two lines of the input. 74The default starting location is 75.Dq Li "-n 10" , 76or the last 10 lines of the input. 77.Pp 78The options are as follows: 79.Bl -tag -width indent 80.It Fl b Ar number 81The location is 82.Ar number 83512-byte blocks. 84.It Fl c Ar number 85The location is 86.Ar number 87bytes. 88.It Fl f 89The 90.Fl f 91option causes 92.Nm 93to not stop when end of file is reached, but rather to wait for additional 94data to be appended to the input. 95The 96.Fl f 97option is ignored if the standard input is a pipe, but not if it is a FIFO. 98.It Fl F 99The 100.Fl F 101option implies the 102.Fl f 103option, but 104.Nm 105will also check to see if the file being followed has been renamed or rotated. 106The file is closed and reopened when 107.Nm 108detects that the filename being read from has a new inode number. 109The 110.Fl F 111option is ignored if reading from standard input rather than a file. 112.It Fl n Ar number 113The location is 114.Ar number 115lines. 116.It Fl q 117Suppresses printing of headers when multiple files are being examined. 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 , c 124and 125.Fl n 126options. 127When the 128.Fl r 129option is specified, these options specify the number of bytes, lines 130or 512-byte blocks to display, instead of the bytes, lines or blocks 131from the beginning or end of the input from which to begin the display. 132The default for the 133.Fl r 134option is to display all of the input. 135.El 136.Pp 137If more than a single file is specified, each file is preceded by a 138header consisting of the string 139.Dq Li "==> " Ns Ar XXX Ns Li " <==" 140where 141.Ar XXX 142is the name of the file unless 143.Fl q 144flag is specified. 145.Sh EXIT STATUS 146.Ex -std 147.Sh SEE ALSO 148.Xr cat 1 , 149.Xr head 1 , 150.Xr sed 1 151.Sh STANDARDS 152The 153.Nm 154utility is expected to be a superset of the 155.St -p1003.2-92 156specification. 157In particular, the 158.Fl F , 159.Fl b 160and 161.Fl r 162options are extensions to that standard. 163.Pp 164The historic command line syntax of 165.Nm 166is supported by this implementation. 167The only difference between this implementation and historic versions 168of 169.Nm , 170once the command line syntax translation has been done, is that the 171.Fl b , 172.Fl c 173and 174.Fl n 175options modify the 176.Fl r 177option, i.e., 178.Dq Li "-r -c 4" 179displays the last 4 characters of the last line 180of the input, while the historic tail (using the historic syntax 181.Dq Li -4cr ) 182would ignore the 183.Fl c 184option and display the last 4 lines of the input. 185.Sh HISTORY 186A 187.Nm 188command appeared in PWB UNIX. 189