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Shell Functions

Shell functions are a way to group commands for later execution using a single name for the group. They are executed just like a "regular" command. Shell functions are executed in the current shell context; no new process is created to interpret them.

Functions are declared using this syntax:

[ function ] name () { command-list; }

This defines a function named name. The body of the function is the command-list between { and }. This list is executed whenever name is specified as the name of a command. The exit status of a function is the exit status of the last command executed in the body.

When a function is executed, the arguments to the function become the positional parameters during its execution. The special parameter # that gives the number of positional parameters is updated to reflect the change. Positional parameter 0 is unchanged.

If the builtin command return is executed in a function, the function completes and execution resumes with the next command after the function call. When a function completes, the values of the positional parameters and the special parameter # are restored to the values they had prior to function execution.

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