Learn Linux Shell Scripting - Fundamentals of Bash 4.4

Getting help

By now, you're probably afraid that you'll never remember all this. While we're sure that in time, given enough practice, you most certainly will, we understand that it is a lot to take in when you're not as experienced. To make this easier, there is another helpful command besides the man pages. As you might have found (and failed when you tried), man if, or man [[, do not work. If you check these commands with type if and type [[, you'll actually see that they are not commands but shell keywords. For most of the shell builtins and shell keywords, you can use the help command to print some information on what they do and how to use them! Using help is as simple as help if, help [[, help while, and so on. For if-then-else statements, ...