CMSG Linux, Cluster, graphing, and Espresso Guide.

These are tutorials and documentation required to get up to speed with tools we use for research

Bash beginner tutorial

Starting a terminal

In Gnome 2

Goto Applications ->  System Tools -> Terminal

In KDE:

Goto Menu -> System Terminal

Others:

For Unity/Gnome 3,   search for "terminal" under the launcher

Usage

Terminals will usually present a prompt for you to type and this prompt will appear as "$" this means the terminal is ready to receive commands.

First Steps

In this section i will show a command and its output:

Command :

ls

The output will appear as such

[asesma@cmsg tmp]$ ls
cu.save  cu.wfc1  ni.save  ni.wfc1

You can ignore the part that says [asesma....] this is unique to the computer and will be different on yours. Here the output of the command ls is the list that follows on the new line. In this case ls simply gives us the contents of the current directory.

Command:

pwd

the output will appear as such

[asesma@cmsg ~]$ pwd
/home/luke

This command pwd means print directory tree it is used to show the current location of the terminal on the directory tree.

Command:

mkdir

example usage:

[asesma@comp32 ~]$ mkdir  test

If you now check the contents of the current directory you will see a new directory named test created, this command is used to create directories.

Command

cd

Example usage,

[asesma@comp32 ~]$ cd test
[asesma@comp32 test]$

This is used to change the current location of the terminal to another location, so if you type pwd you should see your new location thats different from you previous location, see below for another illustration

[asesma@comp32 ~]$ pwd
/home/asesma
[asesma@comp32 ~]$ cd test
[asesma@comp32 test]$ pwd
/home/asesma/test

In this example the terminal is first located at /home/asesma but after changing directory its moved to /home/asesma/test

Command

cp

Example usage:

[asesma@comp32 lesson]$ cp bands.in  silicon.in
[asesma@comp32 lesson]$ ls
 bands.in  silicon.in

The cp command creates a copy of an existing file with the new name thats passed as the second parameter, in this case bands.in was copied to silicon.in, a listing of the contents of the directory with ls shows the two files.

Command

mv

Example usage:

[asesma@comp32 lesson]$ mv silicon.in  simple.in
[asesma@comp32 lesson]$ ls
bands.in  simple.in

The mv command moves a file from one location to another location, but can also be used as a simple way to rename files. Below is a more comprehensive example:

[asesma@comp32 lesson]$ mkdir crystal
[asesma@comp32 lesson]$ ls
bands.in  crystal  simple.in
[asesma@comp32 lesson]$ mv simple.in  crystal/
[asesma@comp32 lesson]$ ls
bands.in  crystal
[asesma@comp32 lesson]$ ls crystal/
simple.in

We first create a directory named crystal, then move the file simple.in to it, using ls along the way to see the effect of each command.

Command

rm

Example usage:

[asesma@comp32 lesson]$ ls
bands.in  crystal
[asesma@comp32 lesson]$ rm bands.in
[asesma@comp32 lesson]$ ls
crystal

The rm command is used to remove/delete files, it can not delete non-empty directories without the recursive flag as see below:

[asesma@comp32 lesson]$ ls
crystal
[asesma@comp32 lesson]$ rm -r crystal/

Command:

rmdir

Example usage:

[asesma@comp32 lesson]$ ls
crystal
[asesma@comp32 lesson]$ ls crystal/
[asesma@comp32 lesson]$ rmdir crystal/
[asesma@comp32 lesson]$ ls
[asesma@comp32 lesson]$

Here we see a directory that is itself empty, the command ls crystal shows the contents of the crystal directory, the command rmdir is then usedto delete the directory.