JOIN(1)                          User Commands                         JOIN(1)

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 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
       fields from FILE2, all separated by CHAR.

       Important: FILE1 and FILE2 must be sorted on the  join  fields.   E.g.,
       use  `sort  -k  1b,1'  if  `join'  has no options.  If the input is not
       sorted and some lines cannot be  joined,  a  warning  message  will  be
       given.

AUTHOR
       Written by Mike Haertel.

REPORTING BUGS
       Report join bugs to bug-coreutils@gnu.org
       GNU coreutils home page: <http://www.gnu.org/software/coreutils/>
       General help using GNU software: <http://www.gnu.org/gethelp/>

COPYRIGHT
       Copyright  ©  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.

GNU coreutils 7.2                 March 2009                           JOIN(1)