Translations by Namhyung Kim

The <command>uname</command> command with the <emphasis role="strong">-a</emphasis> option, prints all system information, including machine name, kernel name &amp; version, and a few other details. Most useful for checking which kernel you're using.

lsb_release

Executing Commands with Elevated Privileges

The following commands will need to be prefaced with the <command>sudo</command> command. Please see <ulink url="https://help.ubuntu.com/community/RootSudo">RootSudo</ulink> for information on using <command>sudo</command>.

Adding a New Group

The <command>addgroup</command> command is used to create a new group on the system. To create a new group, type: <screen>addgroup newgroup</screen> The above command will create a new group called <emphasis role="strong">newgroup</emphasis>.

Adding A New User

The <command>adduser</command> is used to create new users on the system. To create a new user, type: <screen>adduser newuser</screen> The above command will create a new user called <emphasis role="strong">newuser</emphasis>.

To assign a password for the new user use the <command>passwd</command> command: <screen>passwd newuser</screen>

Finally, to assign the new user to the new group, type: <screen>adduser newuser newgroup</screen>

Options

The default behavior for a command may usually be modified by adding a <emphasis role="strong">-- <emphasis>option</emphasis></emphasis> to the command. The <link linkend="ls"><command>ls</command></link> command, for example, has a <emphasis role="strong">-s</emphasis> option so that <command>ls -s</command> will include file sizes in the listing. There is also a <emphasis role="strong">-h</emphasis> option to get those sizes in a "human readable" format.

Options can be grouped in clusters so <screen>ls -sh</screen> is exactly the same command as <screen>ls -s -h</screen> Most options have a long version, prefixed with two dashes instead of one, so even <screen>ls --size --human-readable</screen> is the same command.

"Man" and getting help

<emphasis role="strong"><emphasis>command</emphasis> --help</emphasis> and <emphasis role="strong">man <emphasis>command</emphasis></emphasis> are the two most important tools at the command line.

Virtually all commands understand the <emphasis role="strong">-h</emphasis> (or <emphasis role="strong">--help</emphasis>) option which will produce a short usage description of the command and it's options, then exit back to the command prompt. Type <screen>man -h</screen> or <screen>man --help</screen> to see this in action.

Every command and nearly every application in Linux will have a man (manual) file, so finding them is as simple as typing <command>man command</command> to bring up a longer manual entry for the specified command. For example, <screen>man mv</screen> will bring up the <command>mv</command> (move) manual.

Move up and down the man file with the arrow keys, and quit back to the command prompt with <keycap>q</keycap>.

<screen>man man</screen> will bring up the manual entry for the <command>man</command> command, which is a good place to start.

<screen>man intro</screen> is especially useful - it displays the "Introduction to user commands" which is a well-written, fairly brief introduction to the Linux command line.

There are also <command>info</command> pages, which are generally more in-depth than <command>man</command> pages. Try <screen>info info</screen> for the introduction to info pages.

Searching for man files

If you aren't sure which command or application you need to use, you can try searching the man files.

This is the same as the <command>apropos</command> command.

<command>man -k foo</command>, will search the man files for <emphasis>foo</emphasis>. Try <screen>man -k thunar</screen> to see how this works. <placeholder-1/>

This is the same as the <command>whatis</command> command.