phpman > man > join(1)

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⚡ TLDR: join (tldr-pages)

Join lines of two sorted files on a common field.

Join two files on the first (default) field
join {{path/to/file1}} {{path/to/file2}}
Join two files using a comma (instead of a space) as the field separator
join -t ',' {{path/to/file1}} {{path/to/file2}}
Join field3 of file1 with field1 of file2
join -1 {{3}} -2 {{1}} {{path/to/file1}} {{path/to/file2}}
Produce a line for each unpairable line for file1
join -a {{1}} {{path/to/file1}} {{path/to/file2}}
Join a file from `stdin`
cat {{path/to/file1}} | join - {{path/to/file2}}

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 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 sep‐
arated 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 sepa‐
rated 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/>
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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.