Add option to display version and show help with no options

src/eessi/__init__.py

@@ -1 +1 @@
-__version__ = "0.0.4"
+__version__ = "0.0.5"

src/eessi/cli/main.py

@@ -4,15 +4,39 @@
 
 import typer
 
+import eessi
 from eessi.cli.check import app as check_app
 from eessi.cli.init import app as init_app
 from eessi.cli.shell import app as shell_app
 
-app = typer.Typer(help="User-friendly command line interface to EESSI - https://eessi.io")
+app = typer.Typer(
+    help="User-friendly command line interface to EESSI - https://eessi.io",
+    context_settings={"help_option_names": ["-h", "--help"]},
+    no_args_is_help=True,
+)
 
 app.add_typer(check_app)
 app.add_typer(init_app)
 app.add_typer(shell_app)
 
+def version_callback(value: bool):
+    if value:
+        print(f"eessi version {eessi.__version__}")
+        raise typer.Exit()
+
+
+@app.callback()
+def main(
+    version: bool = typer.Option(
+        None,  # default value
+        "-v",  # short option
+        "--version",  # long option
+        help="Show version of eessi CLI",
+        callback=version_callback,
+    ),
+):
+    pass
+
+
 if __name__ == "__main__":
     app()