feat(posix): implement POSIX compliance for CLI standards

src/fabric_cli/commands/config/fab_config_set.py

@@ -3,6 +3,7 @@
 
 import json
 import os
+import sys
 from argparse import Namespace
 from typing import Any
 
@@ -115,4 +116,4 @@ def _handle_fab_config_mode(previous_mode: str, current_mode: str) -> None:
 
             if previous_mode == fab_constant.FAB_MODE_INTERACTIVE:
                 utils_ui.print("Exiting interactive mode. Goodbye!")
-                os._exit(0)
+                sys.exit(fab_constant.EXIT_CODE_SUCCESS)

src/fabric_cli/commands/fs/cp/fab_fs_cp_folder.py

@@ -63,7 +63,7 @@ def copy_folder(
         if not args.force and not utils_ui.prompt_confirm(
             f"Folder '{from_folder.name}' contains items that do not support copying: {unsupported_items_names}. Do you still want to proceed?"
         ):
-            return 0
+            return fab_constant.EXIT_CODE_SUCCESS
 
     supported_items: list[Item] = []
     folders: list[Folder] = []

src/fabric_cli/commands/fs/mv/fab_fs_mv_folder.py

@@ -6,6 +6,7 @@
 
 from fabric_cli.client import fab_api_folders as folders_api
 from fabric_cli.commands.fs.cp import fab_fs_cp_folder as cp_folder
+from fabric_cli.core import fab_constant
 from fabric_cli.core.hiearchy.fab_folder import Folder
 from fabric_cli.core.hiearchy.fab_hiearchy import Workspace
 from fabric_cli.utils import fab_mem_store as utils_mem_store
@@ -56,9 +57,9 @@ def move_folder(
         )
     elif from_folder.parent != to_context:
         _change_folder_parent(from_folder, to_context)
-        return 1
+        return fab_constant.EXIT_CODE_ERROR
 
-    return 0
+    return fab_constant.EXIT_CODE_SUCCESS
 
 
 def move_folders(

src/fabric_cli/core/fab_constant.py

@@ -282,11 +282,18 @@
 ERROR_SPN_AUTH_MISSING = "ServicePrincipalAuthMissing"
 ERROR_JOB_FAILED = "JobFailed"
 
-# Exit codes
+# Exit codes (POSIX compliant)
+# 0 - Success
+# 1 - General errors
+# 2 - Misuse of shell builtins
+# 126 - Command cannot execute
+# 127 - Command not found
+# 128+n - Fatal error signal "n"
 EXIT_CODE_SUCCESS = 0
 EXIT_CODE_ERROR = 1
 EXIT_CODE_CANCELLED_OR_MISUSE_BUILTINS = 2
-EXIT_CODE_AUTHORIZATION_REQUIRED = 4
+EXIT_CODE_CANNOT_EXECUTE = 126  # Used for authorization/permission errors
+EXIT_CODE_COMMAND_NOT_FOUND = 127
 
 # Contextual commands
 OS_COMMANDS = {

src/fabric_cli/core/fab_decorators.py

@@ -6,7 +6,7 @@
 import fabric_cli.core.fab_logger as fab_logger
 from fabric_cli.core.fab_constant import (
     ERROR_UNAUTHORIZED,
-    EXIT_CODE_AUTHORIZATION_REQUIRED,
+    EXIT_CODE_CANNOT_EXECUTE,
     EXIT_CODE_ERROR,
 )
 from fabric_cli.core.fab_exceptions import FabricCLIError
@@ -42,9 +42,9 @@ def wrapper(*args, **kwargs):
                     args[0].command_path,
                     output_format_type=args[0].output_format,
                 )
-                # If the error is an unauthorized error, return 4
+                # If the error is an unauthorized error, return 126 (POSIX: command cannot execute)
                 if e.status_code == ERROR_UNAUTHORIZED:
-                    return EXIT_CODE_AUTHORIZATION_REQUIRED
+                    return EXIT_CODE_CANNOT_EXECUTE
                 # Return a generic error code
                 return EXIT_CODE_ERROR
 

src/fabric_cli/core/fab_parser_setup.py

@@ -67,6 +67,8 @@ def format_help(self):
         help_message = help_message.replace("positional arguments:", "Arg(s):")
         help_message = help_message.replace("options:", "Flags:")
 
+        # Remove help flag from output (it's implicit)
+        # Note: We now use standard -h/--help instead of -help
         help_message = re.sub(
             r"\s*-h, --help\s*(Show help for command|show this help message and exit)?",
             "",
@@ -76,6 +78,8 @@ def format_help(self):
         help_message = help_message.replace("[-h] ", "")
         help_message = help_message.replace("[-help] ", "")
         help_message = help_message.replace("[-help]", "")
+        help_message = help_message.replace("[--help] ", "")
+        help_message = help_message.replace("[--help]", "")
 
         if "Flags:" in help_message:
             flags_section = help_message.split("Flags:")[1].strip()
@@ -162,7 +166,7 @@ def error(self, message):
             fab_logger.log_warning(message)
 
         if self.fab_mode == fab_constant.FAB_MODE_COMMANDLINE:
-            sys.exit(2)
+            sys.exit(fab_constant.EXIT_CODE_CANCELLED_OR_MISUSE_BUILTINS)
 
 
 # Global parser instances
@@ -181,8 +185,8 @@ def create_parser_and_subparsers():
         help="Run commands in non-interactive mode",
     )
 
-    # -version and --version
-    parser.add_argument("-v", "--version", action="store_true")
+    # -v/-V and --version (POSIX compliant: both short and long forms)
+    parser.add_argument("-v", "-V", "--version", action="store_true")
 
     subparsers = parser.add_subparsers(dest="command", required=False)
 

src/fabric_cli/main.py

@@ -1,6 +1,7 @@
 # Copyright (c) Microsoft Corporation.
 # Licensed under the MIT License.
 
+import signal
 import sys
 
 import argcomplete
@@ -16,7 +17,55 @@
 from fabric_cli.utils.fab_commands import COMMANDS
 
 
+# POSIX-compliant signal handler
+def _signal_handler(signum, frame):
+    """
+    Handle POSIX signals gracefully.
+    
+    Args:
+        signum: Signal number
+        frame: Current stack frame
+    """
+    signal_names = {
+        signal.SIGINT: "SIGINT",
+        signal.SIGTERM: "SIGTERM",
+        signal.SIGHUP: "SIGHUP",
+        signal.SIGQUIT: "SIGQUIT",
+    }
+
+    signal_name = signal_names.get(signum, f"Signal {signum}")
+
+    # Print to stderr as per POSIX
+    sys.stderr.write(f"\n{signal_name} received, exiting gracefully...\n")
+    sys.stderr.flush()
+
+    # Exit with 128 + signal number (POSIX convention)
+    sys.exit(128 + signum)
+
+
+def _setup_signal_handlers():
+    """
+    Setup POSIX-compliant signal handlers.
+    Handles SIGINT, SIGTERM, SIGHUP, and SIGQUIT.
+    """
+    # Handle SIGINT (Ctrl+C)
+    signal.signal(signal.SIGINT, _signal_handler)
+
+    # Handle SIGTERM (termination request)
+    signal.signal(signal.SIGTERM, _signal_handler)
+
+    # Handle SIGQUIT (Ctrl+\)
+    signal.signal(signal.SIGQUIT, _signal_handler)
+
+    # Handle SIGHUP (terminal disconnect) - only on Unix-like systems
+    if hasattr(signal, 'SIGHUP'):
+        signal.signal(signal.SIGHUP, _signal_handler)
+
+
 def main():
+    # Setup POSIX-compliant signal handlers
+    _setup_signal_handlers()
+
     parser, subparsers = get_global_parser_and_subparsers()
 
     argcomplete.autocomplete(parser, default_completer=None)

src/fabric_cli/parsers/fab_describe_parser.py

@@ -77,7 +77,7 @@ def _show_commands_supported(args: Namespace) -> None:
                 f"Usage:  {usage_format}\n\n" f"Available elements:\n  {element_list}\n"
             )
             utils_ui.print(custom_message)
-            sys.exit(2)
+            sys.exit(fab_constant.EXIT_CODE_CANCELLED_OR_MISUSE_BUILTINS)
 
 
 def _print_supported_commands_by_element(element_or_path: str) -> None:

src/fabric_cli/parsers/fab_global_params.py

@@ -8,9 +8,11 @@ def add_global_flags(parser) -> None:
 
     Args:
         parser: The argparse parser to add flags to.
+
+    Note: argparse automatically adds -h/--help, so we don't need to add it manually.
     """
-    # Add help flag
-    parser.add_argument("-help", action="help")
+    # Note: -h/--help is automatically added by argparse by default
+    # We don't need to explicitly add it
 
     # Add format flag to override output format
     parser.add_argument(