NAME

       combine - combine sets of lines from two files using boolean operations

SYNOPSIS

       combine file1 and file2

       combine file1 not file2

       combine file1 or file2

       combine file1 xor file2

       _ file1 and file2 _

       _ file1 not file2 _

       _ file1 or file2 _

       _ file1 xor file2 _

DESCRIPTION

       combine combines the lines in two files. Depending on the boolean operation specified, the contents will
       be combined in different ways:

       and Outputs lines that are in file1 if they are also present in file2.

       not Outputs lines that are in file1 but not in file2.

       or  Outputs lines that are in file1 or file2.

       xor Outputs lines that are in either file1 or file2, but not in both files.

       "-" can be specified for either file to read stdin for that file.

       The  input  files need not be sorted, and the lines are output in the order they occur in file1 (followed
       by the order they occur in file2 for the two "or" operations). Bear in mind  that  this  means  that  the
       operations  are  not  commutative;  "a  and  b"  will not necessarily be the same as "b and a". To obtain
       commutative behavior sort and uniq the result.

       Note that this program can be installed as "_" to allow for the syntactic sugar shown in the latter  half
       of the synopsis (similar to the test/[ command). It is not currently installed as "_" by default, but you
       can alias it to that if you like.

SEE ALSO

       join(1)

AUTHOR

       Copyright 2006 by Joey Hess <id@joeyh.name>

       Licensed under the GNU GPL.

moreutils                                          2024-02-25                                         COMBINE(1)