Functions

Part of the Bash course

By now your scripts are starting to repeat themselves. Maybe you log a timestamped message in three different places, or you check whether a file exists before touching it, over and over, with the same three lines each time. Copying and pasting those lines works, until you need to fix a bug in them and discover you have to fix it in five places at once.

Think about a recipe card. You do not rewrite the steps for scrambled eggs every time you feel like eggs, you write the recipe once, put a name on the card, and from then on you just say "make the scrambled eggs" and everyone knows which steps you mean. A function is that recipe card for Bash: a block of commands, given a name, that you can run by writing the name instead of the commands themselves. ...