Essa é a sintaxe para definir uma função de shell. Consulte a seção Funções da Shell do Bash manual . Começa:
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. When the name of a shell function is used as a simple command name, the list of commands associated with that function name is executed. Shell functions are executed in the current shell context; no new process is created to interpret them.
Functions are declared using this syntax:
name () compound-command [ redirections ]
Espera que você digite um comando composto. Por exemplo:
$ foo()
> {
> echo 'you said foo'
> }
$ foo
you said foo