Manual: join

JOIN(1)						   General Commands Manual					     JOIN(1)

NAME
       join  -	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.

SYNOPSIS
       join [-a ] [-v ] [-e ] [-i|--ignore-case] [-j ] [-o ] [-t ] [-1 ] [-2 ] [--check-order] [--nocheck-order]  [--header]
       [-z|--zero-terminated] [-h|--help] [-V|--version]  

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.

OPTIONS
       -a 
	      also print unpairable lines from file FILENUM, where FILENUM is 1 or 2, corresponding to FILE1 or FILE2

	      Possible values:

		     • 1

		     • 2

       -v 
	      like -a FILENUM, but suppress joined output lines

	      Possible values:

		     • 1

		     • 2

       -e 
	      replace missing input fields with EMPTY

       -i, --ignore-case
	      ignore differences in case when comparing fields

       -j 
	      equivalent to '-1 FIELD -2 FIELD'

       -o 
	      obey FORMAT while constructing output line

       -t 
	      use CHAR as input and output field separator

       -1 
	      join on this FIELD of file 1

       -2 
	      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

       -h, --help
	      Print help

       -V, --version
	      Print version

VERSION
       v(uutils coreutils) 0.8.0

							 2026-04-16						     JOIN(1)