Aliases are simple to understand, but they have some shortcomings as a means of writing your own commands. One of the biggest problems is that they have no way of modifying their behavior based on any arguments given to them; they are just simple text substitutions.
For example, suppose you wanted to make an alias, mkcd, that created a directory before changing into it—a very useful shortcut! If you wanted to do this with aliases, you might try to define it like this, separating each command with a semicolon:
bash$ alias mkcd='mkdir -p;cd'
But this doesn't work:
bash$ mkcd createme mkdir: missing operand Try 'mkdir --help' for more information. -bash: cd: createme: No such file or directory
If we use ...
