gnuplot --version (return code: 0)
gnuplot 5.0 patchlevel 7
gnuplot --help (return code: 0)
Usage: gnuplot [OPTION] ... [FILE]
for X11 options see 'help X11->command-line-options'
-V, --version
-h, --help
-p --persist
-d --default-settings
-c scriptfile ARG1 ARG2 ...
-e "command1; command2; ..."
gnuplot 5.0 patchlevel 7