If you run the same commands in Linux (or Ubuntu) all the time, you can add what is called an "alias" to your user account. For example, I regularly type:
ls -alh
So I setup an alias so that I can just type la. (also, see my Top 10 Aliases list) To do this, simply edit your "profile". Bash is the program that you typically use when you are in a command shell, so it may be called your "bash profile". Your profile is in your Home folder and stores all of your preferences. Just edit the ".profile" or the ".bash_profile" if it exists.
cd ~
pico edit .profile
Add the following code to the bottom:
alias la='ls -alh'
Now when you are typing at the command prompt, you just type la and it acts like you typed ls -alh. Pretty handy.