SCRIPT WORKOUT

Many scripts treat Bash as if it were capable of little more than calling external programs. This is surprising, since version 2 of the default shell has a command set that covers everything from complex string manipulation, through regular expressions, to arrays; useful functions that make expensive program calls redundant. The main advantage of internal functions is that the shell does not need to spawn a new process, which saves processing time and memory. This capability can be important, particularly if you need to launch a program like grep or cut in a loop, as the completion time and memory consumption of a script can explode if you’re not careful. This article describes some simple techiques for speeding up your Bash scripts.