05. Changing file owner and group chown, chgrp, -R
To change the owner and group owner of a file or directory, we use chown (short for change owner). To change a new group, use the similar command chgrp.
We must have root permissions to use this command.
Syntax
The syntax for chown is as follows:
$ chown [options] [owner]:[group] filesThe syntax for chgrp is very similar:
$ chgrp [options] newgroup filesExamples
Here are some functionalities of chown and chgrp that are used in the real world.
1) Changing file owner
To change the file owner, specify the user, then the file name.
$ chown bob sampleFile.txtThe sampleFile.txt file will change user to bob.
2) Changing the group
To change the file's group owner, we set the group name after a colon (:). This provides the same function as chgrp command.
$ chown :programmers todo-list.txt
$ chgrp programmers todo-list.txt3) Changing both file and group ownership
$ chown bob:redditors sampleFile.txtHere, we are changing the sampleFile.txt. The argument before the : indicates the new user, while the argument after shows the new group.
4) Recursive subdirectories and files with -R
To recursively grant ownership of a directory and all files with subdirectories within, use the -R option.
$ chown -R bob /files/folderAn example to wrap things up
Let's go through an example with two users: marie and bob.
marie has access to sudo commands, and wants to copy a file into bob's home directory. She would like to give bob the ownership.
$ sudo cp sampleFile.txt ~bob
Password:
# Copied file to bob's homepage.
$ sudo ls -l ~bob/sampleFile.txt
-rw-r--r-- 1 marie staff 2014-01-13 16:00 /home/bob/sampleFile.txt
# bob only has read access to this file.
$ sudo chown bob: ~bob/sampleFile.txt
-rw-r--r-- 1 bob bob 2014-01-13 16:00 /home/bob/sampleFile.txt
# Now bob has ownership and has write access.Aching back from coding all day?
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