NAME
    join - join lines of two files on a common field

SYNOPSIS
    join [OPTION]... FILE1 FILE2

DESCRIPTION
    For each pair of input lines with identical join fields, write a line
    to standard output. The default join field is the first, delimited by
    whitespace.  When FILE1 or FILE2 (not both) is -, read standard input.

    -a SIDE
    print unpairable lines coming from file SIDE

    -e EMPTY
    replace missing input fields with EMPTY

    -i, --ignore-case ignore differences in case when comparing fields

    -j FIELD
    (obsolescent) equivalent to `-1 FIELD -2 FIELD'

    -j1 FIELD
    (obsolescent) equivalent to `-1 FIELD'

    -j2 FIELD
    (obsolescent) equivalent to `-2 FIELD'

    -o FORMAT
    obey FORMAT while constructing output line

    -t CHAR
    use CHAR as input and output field separator

    -v SIDE
    like -a SIDE, but suppress joined output lines

    -1 FIELD
    join on this FIELD of file 1

    -2 FIELD
    join on this FIELD of file 2

    --help display this help and exit

    --version
    output version information and exit

    Unless -t CHAR is given, leading blanks separate fields and are
    ignored,  else fields are separated by CHAR. Any FIELD is a field num-
    ber counted from 1. FORMAT is one or more comma or blank separated
    specifications, each being `SIDE.FIELD' or `0'. Default FORMAT outputs
    the join field, the remaining fields from FILE1, the remaining fields
    from FILE2, all separated by CHAR.

AUTHOR
    Written by Mike Haertel.

REPORTING BUGS
    Report bugs to <bug-coreutils@gnu.org>.

COPYRIGHT
    Copyright (C) 2002 Free Software Foundation, Inc.
    This is free software; see the source for copying conditions. There is
    NO warranty; not even for MERCHANTABILITY or FITNESS FOR  A PARTICULAR
    PURPOSE.

SEE ALSO
    The full documentation for join is maintained as a Texinfo manual. If
    the info and join programs are properly installed at your site, the
    command

    info join

    should give you access to the complete manual.