A single shell command may be spawned by preceding it with the ! character ($ if using VMS) at the beginning of a command line. Control will return immediately to GNUPLOT after this command is executed. For example, in VMS, AmigaDOS, MS-DOS or OS/2,
! dir
prints a directory listing and then returns to GNUPLOT.
On an Atari, the ! command first checks whether a shell is already loaded and uses it, if available. This is practical if GNUPLOT is run from gulam, for example.