Although you should use the Administrative User identity to do most of your work, there are times (for installations and editing certain files, such as /usr/local/etc/sudoers) when you need to work as the root user.

The su and sudo commands

Just exactly what is meant by su is a subject for debate. A search for su displays such definitions as “switch user,” “substitute user identity,” and “become superuser.” The main idea is present in them all: switching users.

Using su
As the Administrative User, you can become root in these ways:

switches to Administrative User but retains the shell settings of root.

A hyphen in the command resets the shell settings (by reading the .rc file) to those of root.

Using sudo
As the Administrative User, you can use the sudo command to do the following:

See the sudo man page for more information.

The following example shows the Administrative User using the vedituser command:

You can access a list of commands by typing sudo –l. The Administrative User by default, does not need a password to use the sudo command.

Remember, only the root user can edit the /usr/local/etc/sudoers file.

As the root user, you can become another user in two ways, as shown in the following examples:

switches to user, Joe, but retains the shell settings of the previous user, root.

resets the shell settings to those of user, Joe. The pwd command displays Joe’s home directory.

If ever you have an “identity crisis” from changing users too many times, type whoami.