This is the usefulness of aliases. In the above example, the commands rm , mv , and cp will all ask for confirmation before attempting to overwrite a file. This is a good thing so you do not have to type the long form command with options. Setting an alias on a shell is done with the alias command. This option allows you to unalias all currently set aliases.
Functions are pieces of code that perform a special action when called upon from the shell.
You will need to know bash shell programming in order to use functions. Now if you wanted to unpack all tarballs in a current directory, all you would have to do is to use the command unpack , and all tarballs will be unpacked. However, the above function is very simple. You can write much more complex functions, depending on the job to be accomplished. The following are examples of what the bash configuration files can look like.