Permissions decide what the owner and group may do; chown decides who the owner and group are. Set both at once with user:group, which is a root task:
sudo chown deploy:developers report.txt
The forms
sudo chown deploy file # owner only
sudo chown deploy:developers file # owner AND group
sudo chown :developers file # group only (leading colon)
sudo chown deploy: file # owner, and set group to deploy's primary groupRecursively, for a whole tree
sudo chown -R deploy:developers /srv/app-R walks the directory. This is the standard fix after deploying files as the wrong user, or after a git clone/tar as root left everything owned by root. It pairs with recursive chmod when both owner and mode are wrong.
chown vs chgrp, and who is allowed
- Changing the owner always needs root. A normal user cannot give a file away to someone else (that would let people dodge quotas and plant files).
- Changing only the group can be done by the file's owner with
chgrp, but only to a group they themselves belong to:
chgrp developers report.txt # owner can do this if they're in developersSo chgrp (or chown :group) is sometimes available without sudo; reassigning the owner never is.
The classic case: a root-owned file you cannot edit
You ran something with sudo and now a file in your home is owned by root and you cannot write it. Hand it back:
sudo chown $USER:$USER ~/.config/app/settings.jsonThis is the same root cause behind sudo ssh-keygen making an unusable key: elevation created root-owned files in your space.
FAQ
chown changes the owner (and optionally the group); chgrp changes only the group. Changing the owner always requires root. Changing only the group can be done by the file's owner with chgrp, as long as they are a member of the target group.
Changing a file's owner requires root, so run it with sudo. A normal user is not allowed to give files away to other users. If you only need to change the group to one you belong to, use chgrp, which does not require root.
Use -R: sudo chown -R deploy:developers /srv/app. It applies recursively to the directory and everything under it, which is the usual fix after files were created or extracted as the wrong user.
See also
- Linux file permissions explained: what owner and group can each do.
- How to chmod recursively: fix modes across a tree alongside ownership.
- How to create a group on Linux: the groups you assign here.
- Fix SSH "permissions are too open": the root-owned-key case chown solves.
Sources
Authoritative references this article was fact-checked against.
