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. 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.\" 34.Dd June 20, 2020 35.Dt TAIL 1 36.Os 37.Sh NAME 38.Nm tail 39.Nd display the last part of files 40.Sh SYNOPSIS 41.Nm 42.Oo 43.Fl F | 44.Fl f | 45.Fl r 46.Oc 47.Oo 48.Fl q | 49.Fl v 50.Oc 51.Oo 52.Fl b Ar number | 53.Fl c Ar number | 54.Fl n Ar number 55.Oc 56.Op Ar 57.Sh DESCRIPTION 58The 59.Nm 60utility displays the contents of 61.Ar file 62or, by default, its standard input, to the standard output. 63.Pp 64The display begins at a byte, line or 512-byte block location in the 65input. 66Numbers having a leading plus 67.Dq ( + ) 68sign are relative to the beginning 69of the input, for example, 70.Dq -c +2 71starts the display at the second 72byte of the input. 73Numbers having a leading minus 74.Dq ( - ) 75sign or no explicit sign are 76relative to the end of the input, for example, 77.Dq -n 2 78displays the last two lines of the input. 79The default starting location is 80.Dq -n 10 , 81or the last 10 lines of the input. 82.Pp 83The options are as follows: 84.Bl -tag -width Ds 85.It Fl b Ar number 86The location is 87.Ar number 88512-byte blocks. 89.It Fl c Ar number 90The location is 91.Ar number 92bytes. 93.It Fl f 94The 95.Fl f 96option causes 97.Nm 98to not stop when end of file is reached, but rather to wait for additional 99data to be appended to the input. 100The 101.Fl f 102option is ignored if the standard input is a pipe, but not if it is a FIFO. 103.It Fl F 104The 105.Fl F 106option implies the 107.Fl f 108option, but 109.Nm 110will also check to see if the file being followed has been renamed or rotated. 111The file is closed and reopened when 112.Nm 113detects that the filename being read from has a new inode number. 114The 115.Fl F 116option is ignored if reading from standard input rather than a file. 117.It Fl n Ar number 118The location is 119.Ar number 120lines. 121.It Fl q 122Suppresses printing of headers when multiple files are being examined. 123.It Fl r 124The 125.Fl r 126option causes the input to be displayed in reverse order, by line. 127Additionally, this option changes the meaning of the 128.Fl b , 129.Fl c 130and 131.Fl n 132options. 133When the 134.Fl r 135option is specified, these options specify the number of bytes, lines 136or 512-byte blocks to display, instead of the bytes, lines or blocks 137from the beginning or end of the input from which to begin the display. 138The default for the 139.Fl r 140option is to display all of the input. 141.It Fl v 142Always prints a header for each file, even if only a single file is 143specified. 144.El 145.Pp 146If more than a single file is specified, or the 147.Fl v 148flag is used, each file is preceded by a header consisting of the string 149.Dq ==> XXX <== 150where 151.Dq XXX 152is the name of the file. 153The 154.Fl q 155flag disables the printing of the header in both cases. 156.Sh EXIT STATUS 157.Ex -std 158.Sh SEE ALSO 159.Xr cat 1 , 160.Xr head 1 , 161.Xr sed 1 , 162.Xr tac 1 163.Sh STANDARDS 164The 165.Nm 166utility is expected to be a superset of the 167.St -p1003.2-92 168specification. 169In particular, the 170.Fl F , 171.Fl b 172and 173.Fl r 174options are extensions to that standard. 175.Pp 176The historic command line syntax of 177.Nm 178is supported by this implementation. 179The only difference between this implementation and historic versions 180of 181.Nm , 182once the command line syntax translation has been done, is that the 183.Fl b , 184.Fl c 185and 186.Fl n 187options modify the 188.Fl r 189option, i.e. 190.Dq -r -c 4 191displays the last 4 characters of the last line 192of the input, while the historic tail (using the historic syntax 193.Dq -4cr ) 194would ignore the 195.Fl c 196option and display the last 4 lines of the input. 197.Sh HISTORY 198A 199.Nm 200command appeared in PWB 201.Ux . 202