Executing Commands

Commands in a shell may be one of two basic types: a shell builtin or an executable program. The latter may be a compiled executable binary or a text script written in a scripting language.

To see where a command lives, use the type command. For instance,

$ type cd mkdir rm
cd is a shell builtin
mkdir is /bin/mkdir
rm is aliased to `rm -i'

[csh: use which]