Sh
Sh is a shell or commandline interpreter. It refers to the original Stephen Bourne Shell which was later developed by Ken Thompson and John MasheySh in Puppy
The original limited sh is used no longer it usually is just a Symlink symlink to one of the others like the Bash (Bourne again shell), that has become quasi standard in Linux, as it is part of the GNU Utilities from the Free Software Foundation.Also see
Shell ShellsAsh
AshCommands
Bash
BashCommands
WikiPedia:Bourne_shell