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 FILENUM
              print  unpairable  lines coming from file FILENUM, where FILENUM
              is 1 or 2, corresponding to FILE1 or FILE2

       -e EMPTY
              replace missing input fields with EMPTY

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

       -j FIELD
              equivalent to `-1 FIELD -2 FIELD'

       -o FORMAT
              obey FORMAT while constructing output line

       -t CHAR
              use CHAR as input and output field separator

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

       -1 FIELD
              join on this FIELD of file 1

       -2 FIELD
              join on this FIELD of file 2

       --check-order
              check that the input is correctly  sorted,  even  if  all  input
              lines are pairable

       --nocheck-order
              do not check that the input is correctly sorted

       --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 `FILENUM.FIELD' or `0'.  Default FORMAT out-
       puts  the  join  field,  the remaining fields from FILE1, the remaining
       GNU coreutils home page: <http://www.gnu.org/software/coreutils/>
       General help using GNU software: <http://www.gnu.org/gethelp/>

COPYRIGHT
       Copyright  (C) 2009 Free Software Foundation, Inc.  License GPLv3+: GNU
       GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
       This is free software: you are free  to  change  and  redistribute  it.
       There is NO WARRANTY, to the extent permitted by law.

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 coreutils 'join invocation'

       should give you access to the complete manual.