The format for running the
hello program is:
hello option …
With no options,
hello prints the greeting ‘Hello,
hello supports the following options:
Output text instead of the default greeting.
Print an informative help message on standard output and exit successfully.
For the --help output of GNU programs, it’s strongly encouraged to include a brief (one or two sentences) description of what the program does, as well as the synopsis of how to run the program. Any environment variables which affect execution should also be mentioned (Hello doesn’t have any).
Output the traditional greeting message ‘hello, world’.
Print the version number and licensing information of Hello on standard output and then exit successfully.
If more than one of the greeting options (-g, -t, and their long-named equivalents) is specified, whichever comes last takes precedence.