Other Metacharacters

You can can insert comments into shell scripts by using the # symbol when it is the first character in a word. Any following words are treated as comments until a newline occurs (e.g., # This is a comment). This is explained in “Commenting”.

The tilde substitution symbol ~ allows path name substitution and is explained in “Tilde Substitution”.

The % symbol allows job number substitution and is discussed in “Putting Jobs in Background/Foreground”, and under bg, fg, and kill in Chapter 24 “Command Reference”.