JOIN(1)                         User Commands                        JOIN(1)

NAME         top

       join - join lines of two files on a common field

SYNOPSIS         top

       join [OPTION]... FILE1 FILE2

DESCRIPTION         top

       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 blanks.

       When FILE1 or FILE2 (not both) is -, read standard input.

       -a FILENUM
              also print unpairable lines 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 that the input is correctly sorted, even if all input
              lines are pairable

              do not check that the input is correctly sorted

              treat the first line in each file as field headers, print them
              without trying to pair them

       -z, --zero-terminated
              line delimiter is NUL, not newline

       --help display this help and exit

              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
       number counted from 1.  FORMAT is one or more comma or blank
       separated specifications, each being 'FILENUM.FIELD' or '0'.  Default
       FORMAT outputs the join field, the remaining fields from FILE1, the
       remaining fields from FILE2, all separated by CHAR.  If FORMAT is the
       keyword 'auto', then the first line of each file determines the
       number of fields output for each line.

       Important: FILE1 and FILE2 must be sorted on the join fields.  E.g.,
       use "sort -k 1b,1" if 'join' has no options, or use "join -t ''" if
       'sort' has no options.  Note, comparisons honor the rules specified
       by 'LC_COLLATE'.  If the input is not sorted and some lines cannot be
       joined, a warning message will be given.

AUTHOR         top

       Written by Mike Haertel.

REPORTING BUGS         top

       GNU coreutils online help: <>
       Report join translation bugs to <>

COPYRIGHT         top

       Copyright © 2017 Free Software Foundation, Inc.  License GPLv3+: GNU
       GPL version 3 or later <>.
       This is free software: you are free to change and redistribute it.
       There is NO WARRANTY, to the extent permitted by law.

SEE ALSO         top

       comm(1), uniq(1)

       Full documentation at: <>
       or available locally via: info '(coreutils) join invocation'

COLOPHON         top

       This page is part of the coreutils (basic file, shell and text
       manipulation utilities) project.  Information about the project can
       be found at ⟨⟩.  If you have a
       bug report for this manual page, see 
       ⟨⟩.  This page was obtained from
       the tarball coreutils-8.27.tar.xz fetched from 
       ⟨⟩ on 2017-03-13.  If you discover
       any rendering problems in this HTML version of the page, or you
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       COLOPHON (which is not part of the original manual page), send a mail

GNU coreutils 8.27               March 2017                          JOIN(1)