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.\" %sccs.include.redist.roff% 8.\" 9.\" @(#)tail.1 8.1 (Berkeley) 06/06/93 10.\" 11.Dd 12.Dt TAIL 1 13.Os BSD 4 14.Sh NAME 15.Nm tail 16.Nd display the last part of a file 17.Sh SYNOPSIS 18.Nm tail 19.Op Fl f Li | Fl r 20.Oo 21.Fl b Ar number | 22.Fl c Ar number | 23.Fl n Ar number 24.Oc 25.Op Ar file ... 26.Sh DESCRIPTION 27The 28.Nm tail 29utility displays the contents of 30.Ar file 31or, by default, its standard input, to the standard output. 32.Pp 33The display begins at a byte, line or 512-byte block location in the 34input. 35Numbers having a leading plus (``+'') sign are relative to the beginning 36of the input, for example, 37.Dq -c +2 38starts the display at the second 39byte of the input. 40Numbers having a leading minus (``-'') sign or no explicit sign are 41relative to the end of the input, for example, 42.Dq -n 2 43displays the last two lines of the input. 44The default starting location is 45.Dq -n 10 , 46or the last 10 lines of the input. 47.Pp 48The options are as follows: 49.Bl -tag -width Ds 50.It Fl b Ar number 51The location is 52.Ar number 53512-byte blocks. 54.It Fl c Ar number 55The location is 56.Ar number 57bytes. 58.It Fl f 59The 60.Fl f 61option causes 62.Nm tail 63to not stop when end of file is reached, but rather to wait for additional 64data to be appended to the input. 65The 66.Fl f 67option is ignored if the standard input is a pipe, but not if it is a FIFO. 68.It Fl n Ar number 69The location is 70.Ar number 71lines. 72.It Fl r 73The 74.Fl r 75option causes the input to be displayed in reverse order, by line. 76Additionally, this option changes the meaning of the 77.Fl b , 78.Fl c 79and 80.Fl n 81options. 82When the 83.Fl r 84option is specified, these options specify the number of bytes, lines 85or 512-byte blocks to display, instead of the bytes, lines or blocks 86from the beginning or end of the input from which to begin the display. 87The default for the 88.Fl r 89option is to display all of the input. 90.El 91.Pp 92If more than a single file is specified, each file is preceded by a 93header consisting of the string 94.Dq ==> XXX <== 95where 96.Dq XXX 97is the name of the file. 98.Pp 99The 100.Nm tail 101utility exits 0 on success, and >0 if an error occurs. 102.Sh SEE ALSO 103.Xr cat 1 , 104.Xr head 1 , 105.Xr sed 1 106.Sh STANDARDS 107The 108.Nm tail 109utility is expected to be a superset of the POSIX 1003.2 110specification. 111In particular, the 112.Fl b 113and 114.Fl r 115options are extensions to that standard. 116.Pp 117The historic command line syntax of 118.Nm tail 119is supported by this implementation. 120The only difference between this implementation and historic versions 121of 122.Nm tail , 123once the command line syntax translation has been done, is that the 124.Fl b , 125.Fl c 126and 127.Fl n 128options modify the 129.Fl r 130option, i.e. ``-r -c 4'' displays the last 4 characters of the last line 131of the input, while the historic tail (using the historic syntax ``-4cr'') 132would ignore the 133.Fl c 134option and display the last 4 lines of the input. 135.Sh HISTORY 136A 137.Nm tail 138command appeared in 139.At v7 . 140