Here are just some morsels of information about the Linux Command line, and more specifically, Ubuntu Linux Command line / system.

• Users can be added to a group with the command:

sudo adduser <username> <groupname>

In ubuntu, the default system shell is “Dash”. That does speed up your system boot, but it also introduces problems with those scripts which are designed to run in bash, but use /bin/sh to execute. (Which is a surprising amount… this has solved many problems for me. Especially with Asterisk and freePBX.)

• To set Ubuntu back to using bash from dash, run the following command…

cd /bin && sudo rm sh && sudo ln -s /bin/bash /bin/sh

• To add a user to the sudoer list (the list that controls who can use “sudo”) use the command

sudo visudo

• Add a user underneath the “# User privalage specification” comment. If you want just a bog standard sudo user, able to do all on the system, add the line:

<username>    ALL=(ALL) ALL

• ?Fun? tip: add “insults” to the end of the list of “Defaults” in visudo, so it will look like:

Defaults        !lecture,tty_tickets,!fqdn,insults

• The system will insult you every time you enter your sudo password wrongly. For a random example, it just gave me this when I deliberately triggered it:

You speak an infinite deal of nothing

• In Firefox, select the address bar quickly by hitting the “F6” key.

• Type “pwd” to get the full path to your current directory. e.g.:

kirrus@asus:~$ pwd
/home/kirrus

• Monit is a useful program, that gives you a good way of keeping an eye on your servers, making sure they don’t run out of harddisk space, or get a high CPU load. It can either perform some function (like stopping a program from running) during high CPU, or send you a warning email.

http://debianhelp.co.uk/monit.htm (useful howto/basic guide)

http://www.tildeslash.com/monit/ (main website)

Monit is in the ubuntu repositories:

aptitude install monit