Examples:

XSPEC> setp c LA OT Testing      ! PLT label command

XSPEC> setp c LWidth 5           ! PLT line-width command

XSPEC> setplot lis               ! List the PLT command stack.

  1: LAbel OT Testing

  2: LWidth 5

XSPEC> setplot del 1             ! Delete the first command in the stack.

XSPEC> setplot lis

 1: LWidth 5