feat(cli): add show <command> subcommand with mock data

- Implemented `show <command>` subcommand to display description, usage, example, and notes
- Added mock data for ls, grep, cat, mkdir
- Improved output formatting with colors and sections
- Added tests for valid and invalid commands in test_cli.py

Author: mt798jx

.gitignore

@@ -1,6 +1,7 @@
 ## USER ADDED
 .env.secret
 .vscode/
+.idea/
 
 # MkDocs (no longer used - using Ibis HTML directly)
 site/

cli/cli.py

@@ -1,12 +1,14 @@
 import typer
+from commands import hello, show
 
-from commands import hello
-
-# Create the root CLI app
+# Root CLI app
 app = typer.Typer(help="101 Linux Commands CLI 🚀")
 
 # Register subcommands
 app.add_typer(hello.app, name="hello")
 
+# register show directly as command
+app.command()(show.show)
+
 if __name__ == "__main__":
-    app()
+    app()

cli/commands/show.py

@@ -0,0 +1,96 @@
+import typer
+from typing import Dict, TypedDict
+
+class CommandInfo(TypedDict):
+    description: str
+    usage: str
+    example: str
+    notes: str
+
+
+COMMANDS: Dict[str, CommandInfo] = {
+    "ls": {
+        "description": (
+            "List information about the files in the current directory (the default). "
+            "Options can be used to modify the output format, sort order, and more."
+        ),
+        "usage": "ls [OPTION]... [FILE]...",
+        "example": "ls -la /var/log",
+        "notes": (
+            "- `-l` : use a long listing format\n"
+            "- `-a` : show hidden files (starting with `.`)\n"
+            "- `-h` : with -l, print sizes in human-readable format (e.g., 1K, 234M)"
+        ),
+    },
+    "grep": {
+        "description": (
+            "Search input files for lines containing a match to the given PATTERN. "
+            "Often used for filtering log files or searching through code."
+        ),
+        "usage": "grep [OPTION]... PATTERN [FILE]...",
+        "example": 'grep -R "TODO" .',
+        "notes": (
+            "- `-i` : ignore case distinctions\n"
+            "- `-R` : recursively search subdirectories\n"
+            "- `-n` : show line numbers of matches"
+        ),
+    },
+    "cat": {
+        "description": (
+            "Concatenate files and print on the standard output. "
+            "Often used to quickly view file contents."
+        ),
+        "usage": "cat [OPTION]... [FILE]...",
+        "example": "cat /etc/passwd",
+        "notes": (
+            "- `-n` : number all output lines\n"
+            "- `-b` : number non-blank lines\n"
+            "- Use with pipes: `cat file.txt | grep pattern`"
+        ),
+    },
+    "mkdir": {
+        "description": (
+            "Create directories if they do not already exist. "
+            "By default, it creates a single directory."
+        ),
+        "usage": "mkdir [OPTION]... DIRECTORY...",
+        "example": "mkdir -p projects/python/app",
+        "notes": (
+            "- `-p` : create parent directories as needed\n"
+            "- `-v` : print a message for each created directory"
+        ),
+    },
+}
+
+
+def show(
+        command: str = typer.Argument(..., help="Linux command to show details for")
+) -> None:
+    """
+    Display description, usage, examples, and notes for a given Linux command.
+    """
+
+    key = command.strip()
+    info = COMMANDS.get(key)
+
+    if not info:
+        typer.secho(
+            f"✖ Unknown command '{command}'. Try one of: {', '.join(sorted(COMMANDS))}",
+            err=True,
+            fg=typer.colors.RED,
+        )
+        raise typer.Exit(code=1)
+
+    typer.secho(f"\nCommand: {key}\n", fg=typer.colors.CYAN, bold=True)
+
+    typer.secho("Description:", fg=typer.colors.MAGENTA, bold=True)
+    typer.echo(f"  {info['description']}\n")
+
+    typer.secho("Usage:", fg=typer.colors.MAGENTA, bold=True)
+    typer.echo(f"  {info['usage']}\n")
+
+    typer.secho("Example:", fg=typer.colors.MAGENTA, bold=True)
+    typer.echo(f"  {info['example']}\n")
+
+    typer.secho("Notes:", fg=typer.colors.MAGENTA, bold=True)
+    typer.echo(f"{info['notes']}\n")

cli/test_cli.py

@@ -5,58 +5,82 @@
 import subprocess
 import sys
 
+CLI = [sys.executable, "cli.py"]
+CWD = os.path.dirname(__file__)
 
-def test_cli_help():
-    """Test that the CLI shows help."""
-    result = subprocess.run(
-        [sys.executable, "cli.py", "--help"],
+
+def run_cli(args):
+    """Helper to run CLI with subprocess."""
+    return subprocess.run(
+        CLI + args,
         capture_output=True,
         text=True,
-        cwd=os.path.dirname(__file__),
-    )
+        cwd=CWD,
+        )
+
+
+def test_cli_help():
+    """Test that the CLI shows help."""
+    result = run_cli(["--help"])
     assert result.returncode == 0
     assert "101 Linux Commands CLI" in result.stdout
 
 
 def test_hello_command():
     """Test the hello command."""
-    result = subprocess.run(
-        [sys.executable, "cli.py", "hello", "greet"],
-        capture_output=True,
-        text=True,
-        cwd=os.path.dirname(__file__),
-    )
+    result = run_cli(["hello", "greet"])
     assert result.returncode == 0
     assert "Hello, World!" in result.stdout
 
 
 def test_hello_command_with_name():
     """Test the hello command with a custom name."""
-    result = subprocess.run(
-        [sys.executable, "cli.py", "hello", "greet", "--name", "Linux"],
-        capture_output=True,
-        text=True,
-        cwd=os.path.dirname(__file__),
-    )
+    result = run_cli(["hello", "greet", "--name", "Linux"])
     assert result.returncode == 0
     assert "Hello, Linux!" in result.stdout
 
 
 def test_hello_help():
     """Test the hello command help."""
-    result = subprocess.run(
-        [sys.executable, "cli.py", "hello", "--help"],
-        capture_output=True,
-        text=True,
-        cwd=os.path.dirname(__file__),
-    )
+    result = run_cli(["hello", "--help"])
     assert result.returncode == 0
     assert "Hello command group" in result.stdout
 
 
+# ----------------------------
+# Tests for `show` subcommand
+# ----------------------------
+
+def test_show_ls():
+    """Test the show command with ls."""
+    result = run_cli(["show", "ls"])
+    assert result.returncode == 0
+    assert "# ls" in result.stdout or "Command: ls" in result.stdout
+    assert "List" in result.stdout
+
+
+def test_show_grep():
+    """Test the show command with grep."""
+    result = run_cli(["show", "grep"])
+    assert result.returncode == 0
+    assert "grep" in result.stdout
+    assert "Search" in result.stdout or "Print" in result.stdout
+
+
+def test_show_invalid():
+    """Test the show command with an invalid command."""
+    result = run_cli(["show", "foobar"])
+    assert result.returncode == 1
+    combined_output = result.stdout + result.stderr
+    assert "Unknown command" in combined_output
+
+
 if __name__ == "__main__":
     test_cli_help()
     test_hello_command()
     test_hello_command_with_name()
     test_hello_help()
-    print("✅ All tests passed!")
+    test_show_ls()
+    test_show_grep()
+    test_show_invalid()
+    print("✅ All tests passed!")