complete python implementation of ls

Author: XiaoQuark

implement-shell-tools/ls/ls.py

@@ -0,0 +1,74 @@
+import argparse
+import sys
+import os
+
+parser = argparse.ArgumentParser(
+    prog="ls",
+    description="List directory contents"
+)
+
+parser.add_argument(
+    "-1",
+    "--format",
+    action="store_true",
+    help="List one file per line"
+)
+
+parser.add_argument(
+    "-a",
+    "--all",
+    action="store_true",
+    help="Do not ignore entries starting with ."
+)
+
+parser.add_argument(
+    "paths",
+    nargs="*",
+    help="The file to print"
+)
+
+args = parser.parse_args()
+
+if args.format:
+    separator = "\n"
+else:
+    separator = "  "
+
+multiple_paths = len(args.paths) > 1
+
+file_paths = []
+directory_paths = []
+
+if len(args.paths) == 0:
+    args.paths.append(".")
+
+for path in args.paths:
+    if os.path.isfile(path):
+        file_paths.append(path)
+
+    elif os.path.isdir(path):
+        directory_paths.append(path)
+
+if len(file_paths) > 0:
+    sys.stdout.write(separator.join(file_paths) + "\n")
+
+for path in directory_paths:
+    if multiple_paths:
+        sys.stdout.write("\n" + path + ":\n")
+
+    entries = os.listdir(path)
+    entries.sort()
+
+    if args.all:
+        entries = [".", ".."] + entries
+
+    else:
+        visible_entries = []
+
+        for entry in entries:
+            if not entry.startswith("."):
+                visible_entries.append(entry)
+
+        entries = visible_entries
+
+    sys.stdout.write(separator.join(entries) + "\n")