feat(ls): add Python implementation with color support for directories

- Implement ls/ls.py: Python version of ls utility
- Add -1/--one-per-line flag for single column output
- Add -a/--all flag to show hidden files (dotfiles)
- Color directories in blue using ANSI escape codes
- Sort entries case-insensitively for better readability
- Support custom directory path argument (default to current directory)
- Add error handling with proper exit codes
- Match behavior of JavaScript implementation

Author: Iswanna

implement-shell-tools/cat/cat.py

@@ -0,0 +1,54 @@
+import sys
+import argparse
+
+def read_and_output_files():
+    # 1. Setup Argument Parser (Equivalent to 'commander')
+    parser = argparse.ArgumentParser(description="Python implementation of a basic cat-like utility")
+    parser.add_argument("-n", "--number", action="store_true", help="number all output lines")
+    parser.add_argument("-b", "--number-nonblank", action="store_true", help="number only non-empty lines")
+    parser.add_argument("files", nargs="+", help="files to read")
+
+    args = parser.parse_args()
+
+    try:
+        # 2. Read all file contents (Equivalent to Promise.all / fs.readFile)
+        file_contents = []
+        for file_path in args.files:
+            with open(file_path, "r", encoding="utf-8") as f:
+                file_contents.append(f.read())
+        
+        concatenated_content = "".join(file_contents)
+
+        # 3. Process Logic
+        if args.number:
+            # -n logic: number all lines
+            lines = concatenated_content.split("\n")
+            output = []
+            for index, line in enumerate(lines, start=1):
+                # rjust(6) is equivalent to padStart(6)
+                output.append(f"{str(index).rjust(6)}  {line}")
+            sys.stdout.write("\n".join(output))
+
+        elif args.number_nonblank:
+            # -b logic: number only non-empty lines
+            lines = concatenated_content.split("\n")
+            output = []
+            nonblank_line_number = 0
+            for line in lines:
+                if line.strip() == "":
+                    output.append(line)
+                else:
+                    nonblank_line_number += 1
+                    output.append(f"{str(nonblank_line_number).rjust(6)}  {line}")
+            sys.stdout.write("\n".join(output))
+
+        else:
+            # No flags: standard output
+            sys.stdout.write(concatenated_content)
+
+    except Exception as err:
+        print(f"Error reading multiple files: {err}", file=sys.stderr)
+        sys.exit(1)
+
+if __name__ == "__main__":
+    read_and_output_files()

implement-shell-tools/ls/ls.py

@@ -0,0 +1,58 @@
+import os
+import sys
+import argparse
+
+def run_ls_command():
+    parser = argparse.ArgumentParser()
+    parser.add_argument("-1", "--one-per-line", action="store_true", dest="one")
+    parser.add_argument("-a", "--all", action="store_true")
+    parser.add_argument("path", nargs="?", default=".")
+    args = parser.parse_args()
+
+    # ANSI Color Codes
+    BLUE = '\033[34m'
+    RESET = '\033[0m'
+
+    try:
+        # 1. Get and sort entries
+        directory_entries = os.listdir(args.path)
+        directory_entries.sort(key=str.lower)
+
+        # 2. Filter out dotfiles unless -a is used
+        visible_entries = []
+        if args.all:
+            visible_entries = directory_entries
+        else:
+            for name in directory_entries:
+                if not name.startswith("."):
+                    visible_entries.append(name)
+
+        # 3. Apply colors to folders
+        colored_entries = []
+        for name in visible_entries:
+            # We must join the path to the name to check if it's a folder correctly
+            full_path = os.path.join(args.path, name)
+            
+            if os.path.isdir(full_path):
+                # Wrap the name in Blue color codes
+                colored_entries.append(f"{BLUE}{name}{RESET}")
+            else:
+                # Keep regular file name as is
+                colored_entries.append(name)
+
+        # 4. Build output string
+        output_string = ""
+        if args.one:
+            output_string = "\n".join(colored_entries) + "\n"
+        else:
+            output_string = "  ".join(colored_entries) + "\n"
+
+        if colored_entries:
+            sys.stdout.write(output_string)
+
+    except Exception as err:
+        print(f"Error: {err}", file=sys.stderr)
+        sys.exit(1)
+
+if __name__ == "__main__":
+    run_ls_command()