greycat 1356119031 learn Setting a default value. : "${variable:=DEFAULT}" # The : is necessary. We want the side effects of the parameter expansion, but we don't want to *execute* its value as a command, so we put a null command in front. Soliton 1622453480 forget Soliton 1622453485 learn Setting a default value. : "${variable=DEFAULT}" # The : is necessary. We want the side effects of the parameter expansion, but we don't want to *execute* its value as a command, so we put a null command in front. A perhaps more readable alternative: variable=${variable-DEFAULT}