Computer Science


TAIL(1)                                                   TAIL(1)

NAME
       tail - output the last part of files

SYNOPSIS
       tail  [-c  [+]N[bkm]] [-n [+]N] [-fqv] [--bytes=[+]N[bkm]]
       [--lines=[+]N] [--follow] [--quiet] [--silent] [--verbose]
       [--help] [--version] [file...]

       tail [{-,+}Nbcfklmqv] [file...]

DESCRIPTION
       This  manual page documents the GNU version of tail.  tail
       prints the last part (10 lines by default) of  each  given
       file;  it  reads from standard input if no files are given
       or when a filename of `-' is encountered.   If  more  than
       one  file  is  given, it prints a header consisting of the
       file's name enclosed in `==>' and `<==' before the  output
       for each file.

       The  GNU  tail  can  output any amount of data, unlike the
       Unix version, which uses a fixed size buffer.  It  has  no
       -r  option (print in reverse).  Reversing a file is really
       a different job from printing the end of a file;  the  BSD
       tail  can  only reverse files that are at most as large as
       its buffer, which is typically 32k.  A reliable  and  more
       versatile way to reverse files is the GNU tac command.

   OPTIONS
       tail  accepts  two  option  formats: the new one, in which
       numbers are arguments to the option letters, and  the  old
       one, in which a `+' or `-' and optional number precede any
       option letters.

       If a number (`N') starts with a `+', tail begins  printing
       with  the Nth item from the start of each file, instead of
       from the end.

       -c N, --bytes N
              Tail by N bytes.  N is a nonzero  integer,  option-
              ally followed by one of the following characters to
              specify a different unit.

              b      512-byte blocks.

              k      1-kilobyte blocks.

              m      1-megabyte blocks.

       -f, --follow
              Loop forever trying to read more characters at  the
              end of the file, on the assumption that the file is
              growing.  Ignored if reading from a pipe.  If  more
              than  one file is given, tail prints a header when-
              ever it gets output from a different file, to indi-
              cate which file that output is from.

       -l, -n N, --lines N
              Tail  by  N lines.  -l is only recognized using the
              old option format.

       -q, --quiet, --silent
              Never print filename headers.

       -v, --verbose
              Always print filename headers.

       --help Print a usage message and exit with a  status  code
              indicating success.

       --version
              Print  version  information on standard output then
              exit.

FSF                     GNU Text Utilities                      1

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