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join(1)                           User Commands                          join(1)


       join - join lines of two files on a common field


       join [OPTION]... FILE1 FILE2


       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

       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 STRING
              replace missing (empty) input fields with STRING; I.e., missing
              fields specified with '-12jo' options

       -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.


       Written by Mike Haertel.


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


       Copyright © 2022 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.


       comm(1), uniq(1)

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

GNU coreutils 9.1                  April 2022                            join(1)

coreutils 9.1 - Generated Thu Aug 11 05:56:38 CDT 2022
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