join(1) - Linux man page

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 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.

Important: FILE1 and FILE2 must be sorted on the join fields. E.g., use 'sort -k 1b,1' if 'join' 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

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/>
Report join translation bugs to <http://translationproject.org/team/>

Copyright

Copyright © 2010 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

comm(1), uniq(1)

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 aqjoin invocationaq

should give you access to the complete manual.

Referenced By

combine(1)