TAIL(1)                    OpenBSD Reference Manual                    TAIL(1)

NAME
     tail - display the last part of a file

SYNOPSIS
     tail [-f | -r] [-b number | -c number | -n number] [file ...]

DESCRIPTION
     The tail utility displays the contents of file or, by default, its stan-
     dard input, to the standard output.

     The display begins at a byte, line or 512-byte block location in the in-
     put.  Numbers having a leading plus (``+'') sign are relative to the be-
     ginning of the input, for example, ``-c +2'' starts the display at the
     second byte of the input.  Numbers having a leading minus (``-'') sign or
     no explicit sign are relative to the end of the input, for example, ``-n
     2'' displays the last two lines of the input.  The default starting loca-
     tion is ``-n 10'', or the last 10 lines of the input.

     The options are as follows:

     -b number
             The location is number 512-byte blocks.

     -c number
             The location is number bytes.

     -f      The -f option causes tail to not stop when end-of-file is
             reached, but rather to wait for additional data to be appended to
             the input.  If the file is replaced (ie. the inode number
             changes), tail will reopen the file and continue.  If the file is
             truncated, tail will reset its position back to the beginning.
             This makes tail more useful for watching log files that may get
             rotated.  The -f option is ignored if the standard input is a
             pipe, but not if it is a FIFO.

     -n number
             The location is number lines.

     -r      The -r option causes the input to be displayed in reverse order,
             by line.  Additionally, this option changes the meaning of the
             -b, -c and -n options.  When the -r option is specified, these
             options specify the number of bytes, lines or 512-byte blocks to
             display, instead of the bytes, lines or blocks from the beginning
             or end of the input from which to begin the display.  The default
             for the -r option is to display all of the input.

     If more than a single file is specified, each file is preceded by a head-
     er consisting of the string ``==> XXX <=='' where ``XXX'' is the name of
     the file.

     The tail utility exits 0 on success or >0 if an error occurred.

SEE ALSO
     cat(1),  head(1),  sed(1)

STANDARDS
     The tail utility is expected to be a superset of the IEEE Std1003.2-1992
     (``POSIX.2'') specification.  In particular, the -b and -r options are
     extensions to that standard.

     The historic command line syntax of tail is supported by this implementa-
     tion.  The only difference between this implementation and historic ver-
     sions of tail, once the command line syntax translation has been done, is
     that the -b, -c and -n options modify the -r option, i.e. ``-r -c 4''
     displays the last 4 characters of the last line of the input, while the
     historic tail (using the historic syntax ``-4cr'') would ignore the -c
     option and display the last 4 lines of the input.

HISTORY
     A tail command appeared in Version 7 AT&T UNIX.

OpenBSD 2.6                      June 6, 1993                                2
