Issue #1535 - Add a help command (alias of --help)

changelog.d/1535.feature.md

@@ -0,0 +1,2 @@
+`pipx help COMMAND` can now be used as an alias for `pipx COMMAND --help`,
+where COMMAND is a valid pipx command, or nothing.

src/pipx/commands/__init__.py

@@ -34,4 +34,5 @@
     "pin",
     "unpin",
     "upgrade_interpreters",
+    "help",
 ]

src/pipx/commands/help.py

@@ -0,0 +1,2 @@
+# The help command only reuses existing features
+# This file exists to satisfy __all__ in pipx/commands/__init__.py

src/pipx/main.py

@@ -423,6 +423,15 @@ def run_pipx_command(args: argparse.Namespace, subparsers: Dict[str, argparse.Ar
         return ExitCode(0)
     elif args.command == "environment":
         return commands.environment(value=args.value)
+    elif args.command == "help":
+        if args.subcommand is not None:
+            sys.argv[1] = args.subcommand
+            sys.argv[2] = "--help"
+            return cli()
+        else:
+            parser, _ = get_command_parser()
+            parser.print_help()
+            return ExitCode(0)
     else:
         raise PipxError(f"Unknown command {args.command}")
 
@@ -928,6 +937,21 @@ def _add_environment(subparsers: argparse._SubParsersAction, shared_parser: argp
     p.add_argument("--value", "-V", metavar="VARIABLE", help="Print the value of the variable.")
 
 
+def _add_help(subparsers: argparse._SubParsersAction, shared_parser: argparse.ArgumentParser) -> None:
+    p = subparsers.add_parser(
+        "help",
+        help="Print out help info for pipx or for a particular command (alias of --help).",
+        description="Print out help info for pipx or for a particular command (alias of --help).",
+        parents=[shared_parser],
+    )
+    p.add_argument(
+        "subcommand",
+        choices=commands.__all__,
+        nargs="?",
+        help="Print out help for the specified command, if provided, using pipx help COMMAND",
+    )
+
+
 def get_command_parser() -> Tuple[argparse.ArgumentParser, Dict[str, argparse.ArgumentParser]]:
     venv_container = VenvContainer(paths.ctx.venvs)
 
@@ -973,7 +997,9 @@ def get_command_parser() -> Tuple[argparse.ArgumentParser, Dict[str, argparse.Ar
     )
     parser.man_short_description = PIPX_DESCRIPTION.splitlines()[1]  # type: ignore[attr-defined]
 
-    subparsers = parser.add_subparsers(dest="command", description="Get help for commands with pipx COMMAND --help")
+    subparsers = parser.add_subparsers(
+        dest="command", description="Get help for commands with pipx COMMAND --help\n\t\t\t  or pipx help COMMAND"
+    )
 
     subparsers_with_subcommands = {}
     _add_install(subparsers, shared_parser)
@@ -995,6 +1021,7 @@ def get_command_parser() -> Tuple[argparse.ArgumentParser, Dict[str, argparse.Ar
     _add_runpip(subparsers, completer_venvs.use, shared_parser)
     _add_ensurepath(subparsers, shared_parser)
     _add_environment(subparsers, shared_parser)
+    _add_help(subparsers, shared_parser)
 
     parser.add_argument("--version", action="store_true", help="Print version and exit")
     subparsers.add_parser(