join(1)

GNU coreutils 8.32

March 2020

coreutils

The basic file, shell and text manipulation utilities of the GNU operating system

coreutils-doc

Documentation for the GNU Core Utilities

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 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-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
--header
	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
--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 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

Written by Mike Haertel.

REPORTING BUGS

GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Report any translation bugs to <https://translationproject.org/team/>

COPYRIGHT

Copyright © 2020 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <https://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.

REFERENCED BY

ispell(1)