10.1 Creating Custom Commands

• In most shells, aliases (10.2, 10.3, 10.4) are an easy way to shorten a long command line or do a short series of commands.

• All except the oldest Bourne-type shells have shell functions (10.9). These are a cross between aliases and shell scripts. They're good both for shortening command lines and for running a short or long series of commands.

• You can simulate shell functions (10.10) on older Bourne shells. These "fake functions" don't have much more power than aliases - but they're better than nothing!