tldr/pages/common/join.md

join

Join lines of two sorted files on a common field.

• Join two files on the first (default) field:

join {{file1}} {{file2}}

• Join two files using a comma (instead of space) as a field separator:

join -t ',' {{file1}} {{file2}}

• Join field3 of file1 with field1 of file2:

join -1 3 -2 1 {{file1}} {{file2}}

• Produce a line for each unpairable line for file1:

join -a 1 {{file1}} {{file2}}