Identifier / Programs / Linux and Unix
join
Join lines of two sorted files on a common field. tldr-pages
GTFOBins file-read 1 documented command
How join is abused
file-read
-aEach abuse is GTFOBins's category and the options and words it uses; the full write-up is on GTFOBins's page for join.
1 documented command
file-read unprivileged, with sudo, as SUID
join -a 2 /dev/null /path/to/input-fileThe command the identifier reads trips no Sigma process-creation rule. This command is from GTFOBins, at commit acd524623f9c of 2026-05-27, under the GPL-3.0, with no warranty. Changed: Markdown is shown formatted. The source is in lolbas-gtfobins-commands.json.gz, and the full entry is on GTFOBins’s page for join. The identifier reads the line that runs join.
Everyday use
Join two files on the first (default) field
join path/to/file1 path/to/file2IdentifyJoin two files using a comma (instead of a space) as the field separator
join -t ',' path/to/file1 path/to/file2IdentifyJoin field3 of file1 with field1 of file2
join -1 3 -2 1 path/to/file1 path/to/file2IdentifyNone of the 3 examples the identifier reads matches GTFOBins abuse or trips a Sigma process-creation rule.