The mask must be given in octal representation:
su: Switch user.
Example: > su root
whoami: Who am I ?
chmod: Changing File Permissions
Example: chmod a=r,u+w somefile Explanation: u user (owner) permissions g group permissions o others (public) permissions a all of user, group and others permissions = assign a permission absolutely + add a permission - take away a permission
umask: seting default file permissions.
The mask must be given in octal representation:
Example:
> umask 644
Explanation:
400
200
40
4
---
644
644 is rw-r--r--
the owner can read and write the file or
directory, everybody else can only read it.
Octal numbers corresponding to some common permissions:
755 is rwxr-xr-x
the owner can read, write, and execute the
file, everybody else can read or execute it.
For a directory, this mode is equivalent to
644
711 is rwx--x--x
the owner can read, write, and execute the
file, everybody else can only execute it.
444 is r--r--r--
this permission implies read-only for everybody.
chown: Change file owner and group.
chown [OPTION]... OWNER[:[GROUP]] FILE...
chown [OPTION]... :GROUP FILE...
Options:
-R, --recursive : operate on files and directories recursively
Example:
chown -R felix:users ~/*