11.1.1. What are functions?
Shell functions are a way to group commands for later execution, using a single name for this group, or routine . The name of the routine must be unique within the shell or script. All the commands that make up a function are executed like regular commands. When calling on a function as a simple command name, the list of commands associated with that function name is executed. A function is executed within the shell in which it has been declared: no new process is created to interpret the commands.
Special built-in commands are found before shell functions during command lookup. The special built-ins are: break , : , . , continue , eval , exec , exit , export , readonly , return , set , shift , trap and unset .
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