LPI 1 Notes #2- Introduction to LPIC-1 and Linux


In our very first article, we had a little dive into the Linux World by making a few introductions that are imperative to every new user or enthusiast. In our second article, we are going to learn some cool stuff that will enable you to get some hands on feel of your Distribution.
Tricks on the shell
If you are one of those like me who finds it tedious to type in the whole of the command in a shell, then command-completion is here to rescue you from the tedium. This is pretty simple, if you have typed the first few letters of a command, just hit the tab key and there will be a number of options available for you to accept. If the command exists, it will be automatically completed for you. While trying to get into a specific directory of getting a file which might have a long name, then command-completion comes in handy.
Getting into the basics of commands
Internal and external commands
Internal commands
Internal command are the ones inherent or built into the shell. The discussed shells usually offer similar internal commands though as might be expected there are a few differences here and there. Most of the internal commands enables you to perform some common activities within the shell such as: (examples)
1. Displaying some text

# echo text

2. Changing from one directory to another

# cd /home/

3. Opening an application

# exec vlc

4. Closing the shell

# exit


# logout

4. Timing an operation

# time pwd

5. Displaying the directory you are currently in

# pwd

External commands
These are commands that are not built into the the shell but can be executed by the shell. They are usually checked in PATH environment variable to look for a program that will run it. The PATH environment variable holds the list of directories where commands can be located. Most of the commands are external commands and their documentation are usually provided by the man page. You just type:

# man command

And the documentation of the command is provided.