complete ls exercise

Author: enjoy15

implement-shell-tools/ls/ls.py

@@ -0,0 +1,65 @@
+#!/usr/bin/env python3
+
+import locale
+import os
+import sys
+
+
+def parse_args(args):
+    one_per_line = False
+    show_all = False
+    paths = []
+
+    for arg in args:
+        if arg.startswith("-") and arg != "-":
+            for flag in arg[1:]:
+                if flag == "1":
+                    one_per_line = True
+                elif flag == "a":
+                    show_all = True
+                else:
+                    print(f"ls: invalid option -- '{flag}'", file=sys.stderr)
+                    sys.exit(1)
+        else:
+            paths.append(arg)
+
+    if not one_per_line:
+        print("Usage: ls.py -1 [-a] [path]", file=sys.stderr)
+        sys.exit(1)
+
+    if len(paths) > 1:
+        print("Usage: ls.py -1 [-a] [path]", file=sys.stderr)
+        sys.exit(1)
+
+    return show_all, (paths[0] if paths else ".")
+
+
+def list_entries(path, show_all):
+    try:
+        entries = os.listdir(path)
+    except FileNotFoundError:
+        print(f"ls: cannot access '{path}': No such file or directory", file=sys.stderr)
+        sys.exit(1)
+    except NotADirectoryError:
+        print(os.path.basename(path))
+        return
+
+    if show_all:
+        entries = [".", ".."] + entries
+    else:
+        entries = [name for name in entries if not name.startswith(".")]
+
+    locale.setlocale(locale.LC_COLLATE, "")
+    entries = sorted(entries, key=locale.strxfrm)
+
+    for entry in entries:
+        print(entry)
+
+
+def main():
+    show_all, path = parse_args(sys.argv[1:])
+    list_entries(path, show_all)
+
+
+if __name__ == "__main__":
+    main()