Graphical interfaces are a relatively new addition to computing. Before the graphical interface the command shell was how a user would interface with a computer. As computer technology emerged, the shell became a very powerful tool. Even though today you can perform almost any task by using the graphical interface of Linux, the shell remains on of the most powerful tools that you have at your disposal.

If you are completely new to the Linux environment, you may want to take a look at Matt Fast's emacs/Linux tutorial. It's a step by step ( screenshots included ) guide to getting started in Linux.

1. Navigation

The "cd" command allows you to navigate through the directory structure of Linux. Here are some uses of the cd command and how the command relates to familiar gui interface icons and buttons.

cd: Action -- change to you home directory.
Gui Equivalent -- The "Home" or "My Documents" icon.
cd ..: Action -- change up one directory.
Gui Equivalent -- The "Back" button on a file browser.
cd <dir_name>: Action -- change to the directory named <filename>.
Gui Equivalent -- Clicking on a folder in a file browser.

2. Viewing Files

To date myself and quote Ferris Bueller, "Life moves pretty fast. If you don't stop and look around once in a while, you could miss it." Here are some commands to help you look around while you're programming.

ls: See the names of files and folders in the current directory.
ls -a: See the names of files and folders in the current directory, including hidden files. ( files that start with a '.' character.
ls -l: See the names of files and folders in the current directory, in a detailed list view.
less <file_name>: Open the file <file_name>for reading within the shell. The spacebar scrolls down a page and the 'q' key quits.

3. Directories

Directories can be both created and deleted. The commands "mkdir" and "rmdir" can be used as follows:

mkdir <dir_name>: Create a directory in the current directory named dir_name.
rmdir <dir_name>: Remove the directory in the current directory named dir_name.

4. Creating and Editing Files

Your likely familiar with either emacs or vi at this point, but here's a little reminder.

touch <file_name>: If <filename> doesn't exist, create it. Otherwise, update the timestamp on the file.
emacs <file_name>: Open the file <file_name> for editing with the emacs editor.
emacs -nw <file_name>: Open the file <file_name> for editing with the emacs editor within the shell. Make sure you know the emacs shortcut keys before trying this one.
vi <file_name>: Open the file <file_name> for editing with the vim editor.

5. Moving, Copying and Deleting Files

The following commands are handy when you need to do a little housekeeping in your home directory:

mv <src> <dst>: Move the file <src> to the location <dst>. This is also how you rename files and folders.
cp <src> <dst>: Move the file <src> to the location <dst>. You need to specify an option to the command in order to copy folders. Do you know what it is?
rm <file_name>: Delete the file <file_name>.

6. Advanced Commands

There are litterally hundreds of Linux commands that you can type at the command shell. The following commands are a few that tend to come in handy. I'll leave it as an exercise for the reader to find out what they do.

tar xzvf
tar czvf
pwd
cat
grep
echo
source
kill
chmod
alias

7. Getting More Information

Your TA is not the only, nor the best source for information on the many command line utilities. Here are a few places that you can go searching for more information.

google: Google for it. If it's not on google, it doesn't exist.
info <command_name>: The info command will give you information about a particular <command_name>.
man <command_name>: The man command will also give you information about how to use a specific command and tends to be a bit more complete than info. The man pages also have information about some standard functions.
man -k <partial_command>: If you're unsure about the name of a particular command or funcion you might try throwing man the "-k" option with the part of the command that you remember or a particular hunch you have about what the command or function would be called.

Review of Linux Commands

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