As get to know Linux, you will inevitably use the command line (cli) at some point. Every distribution I have ever installed includes at least one terminal and at least one command interpreter. Most often the interpreter of choice is Bash. I am not going to do a history lesson on Bash other than to say it is an acronym meaning Bourne again shell. If you want to read the history follow the Wiki link above. Bash is a very versatile shell and thus has become widely popular amongst the FOSS community. I cannot think of a distribution that I have run that did not include it by default or at least make it available. Also I should point out that the terminal window itself is not Bash but rather a container for Bash to run in. This is why it might look different from one Linux distro to another.
There are two methods Bash can be run in; as an interactive shell you log into as a user and use the cli exclusively or as an interactive shell from within the graphical environment. Most of the time we are using the latter but if you work on a server, use ssh or are recovering a broken system, then you may find yourself at the login prompt of Bash. I hope that you are not facing that option until you at least have the basics down. System recovery is hard enough on its own let alone trying to remember commands.
To get started using Bash I recommend reading some blogs or websites devoted to Bash. You can also find plenty of books on Bash as well and since the core fundamentals have not changed drastically, even older books found in the used aisles or bargain bins are still very relevant to new users.
To illustrate a simple example you can open a terminal and type pwd. This is the output:
johnny@desert-bear ~ $ pwd
/home/johnny
johnny@desert-bear ~ $
The command pwd provides a method of telling you where you are in the file system. It can be helpful to verify this before running a rm command as root. Notice the prompt is a $ sign. This is the default prompt for an unprivileged user. As root the prompt will turn into the bang symbol # by default. Both of these values and many more can be customized. This is yet another reason that Bash is so popular is that it can be tailored to the user very easily, Any customizations values are stored in the file ~/.bashrc. This file is read upon opening a terminal window using Bash when in an interactive mode.
This versatility and the fact it is found in almost every distro is why you will often see help given in forums as cli commands. They are universal with very few exceptions. In the various distributions graphical environment, the instructions can vary from one distro to another pretty quick. That makes trouble shooting very difficult indeed.
So now we know what it is and the question now is how to use it? Single commands can be run one at a time and for most there will be a help file by typing -h, –help or man ‘command‘ (no quotes and substitute command for the command you are needing to know more about). Commands can be connected together using the pipe symbol | and the command following the | symbol will be run after the first command. Commands can be run together as scripts and I’ll show an example later.
There are many websites and blogs devoted to Bash and the cli. I could fill an entire post with nothing but links there are so many. But this is one I have referred to over and over as I progress in my understanding of Bash; LinuxCommand.org. One more site that is sometimes a bit more advanced but gives practical uses of command is All commands | commandlinefu. The first of these is a basic primer moving into some more advanced techniques and the second allows others to post examples of commands they use for a variety of tasks.
Just today I ran across this example ot a Bash script that can be used for the discovery of large files. I needed this at work about six months ago. 
Notice the start of every Bash script is the same; #! /bin/bash . This #! symbol identifies the following commands are a script and /bin/bash is the working path for finding the commands. Open a text editor and paste the following code into it:
#!/bin/bash
# if nothing is passed to the script, show usage and exit
[[ -n "$1" ]] || { echo “Usage: findlarge [PATHNAME]“; exit 0 ; }
# simple using find, $1 is the first variable passed to the script
find $1 -type f -size +100000k -exec ls -lh {} ; | awk ‘{ print $9 “: ” $5 }’
Notice the two # symbols not followed by an !. These are used to comment on the script. To use this script type as root:
chmod a+x findlarge.sh
This sets the file as an executable and you do this in the same directory as the file or include the path. To run the script as root type:
./findlarge.sh / > largefiles.txt &
This will run the script and output to a text file in the current or working directory. The & symbol at the end tells Bash to run this in the background since this can take a while. Of course the variables of path and file size can be modified to suit your needs. Thanks goes out to Jarrod Goddard for sharing the script and Rackspace for sharing it with him.
Have a favorite example of your own or for more discussion, share in the comments.
Connecting via wireless has got to be in the top 10 of things people want for their computer. So many of us are opting for laptops, netbooks or tablet devices that wireless connectivity becomes a must have function. Fortunately wireless has never been easier with Linux than ever before. But there are still some cases where the driver doesn’t automatically load. I am writing this post for these situations.
The default DVD installation will install quite a few of the most popular packages including Gedit, 