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 | -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 begin-
     ning 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 ex-
     plicit sign are relative to the end of the input, for example, -n 2 dis-
     plays the last two lines of the input.  The default starting location 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.

     -n number | -number
             The location is number lines.

     -f      Do 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 re-
             placed (i.e., the inode number changes), tail will reopen the
             file and continue.  If the file is truncated, tail will reset its
             position to the beginning.  This makes tail more useful for
             watching log files that may get rotated.  The -f option is ig-
             nored if the standard input is a pipe, but not if it is a FIFO.

     -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 begin-
             ning 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.

EXAMPLES
     To display the last 500 lines of the file foo:

           $ tail -500 foo

     Keep /var/log/messages open, displaying to the standard output anything
     appended to the file:

           $ tail -f /var/log/messages

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 dis-
     plays the last 4 characters of the last line of the input, while the his-
     toric 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 2.9                      June 6, 1993                                2
