Implement cat shell tool in Python

Author: ebrahimbeiati

implement-shell-tools/implement-shell-tools-python/cat/cat.py

@@ -0,0 +1,61 @@
+#!/usr/bin/env python3
+import sys
+import os
+
+global_line_counter = 1
+
+def print_file(file_path, options):
+    global global_line_counter
+    try:
+        with open(file_path, "r", encoding="utf-8") as f:
+            content = f.read()
+
+        lines = content.split("\n")
+        if lines and lines[-1] == "":
+            lines.pop()
+
+        for line in lines:
+            prefix = ""
+
+            should_number = (
+                options["number_mode"] == "all" or
+                (options["number_mode"] == "non-empty" and line.strip() != "")
+            )
+
+            if should_number:
+                prefix = f"{global_line_counter:6}\t"
+                global_line_counter += 1
+
+            sys.stdout.write(prefix + line + "\n")
+
+    except Exception as e:
+        print(f"cat: {file_path}: {e}", file=sys.stderr)
+        sys.exit(1)
+
+
+def main():
+    global global_line_counter
+    args = sys.argv[1:]
+
+    options = {"number_mode": "off"}
+    files = []
+
+    for arg in args:
+        if arg == "-n":
+            options["number_mode"] = "all"
+        elif arg == "-b":
+            options["number_mode"] = "non-empty"
+        else:
+            files.append(arg)
+
+    if not files:
+        print("cat: missing file operand", file=sys.stderr)
+        sys.exit(1)
+
+    for file_path in files:
+        global_line_counter = 1
+        print_file(file_path, options)
+
+
+if __name__ == "__main__":
+    main()