You can change the permissions of a file using chmod command: chmod permission_cmd myfile
You can allow or disallow the user (u), group (g) or other(o) the following actions: read (r), write (w) and execute (x).
So, if you want to allow the user (the person who owns it) to execute the file:
chmod u+x myfile
And to disallow the user (the person who owns it) to execute the file:
chmod u-x myfile
Say you want to give the rw permissions to owner and group of a file, you will have to use the following command:
chmod u+r,u+w,g+r,g+w myfile or chmod u+rw,g+rw myfile
To give members of a group ability to modify a file, use:
chmod g+w myfile
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