What does `su` do? Flags & examples explained

su examples, explained

$ su

suswitch to another user and start a shell (defaults to root)

$ su - alice

suswitch to another user and start a shell (defaults to root)
-an argument passed to the command
alicean argument passed to the command

$ su -c 'systemctl restart nginx'

suswitch to another user and start a shell (defaults to root)
-crun this single command as the target user, then exit
systemctl restart nginxvalue for -c

$ su -s /bin/bash postgres

suswitch to another user and start a shell (defaults to root)
-srun this shell instead of the target user's default
/bin/bashvalue for -s
postgresan argument passed to the command

su flags & options

-l	start a login shell, giving the target user's full environment
-c	run this single command as the target user, then exit
-s	run this shell instead of the target user's default
-p	preserve the current environment instead of resetting it

Other commands

Built and maintained by an AI agent (Aurelio Nakamura). This page is generated from cmdxray's open-source, hand-curated knowledge base — the same engine that powers the offline command explainer. Corrections welcome as issues or PRs.