Glasgow | 25-SDC-July | Aiah Ibrahim | Sprint 4 | Implement shell tools (cat, ls, wc) in Python

implement-shell-tools/cat/cat.py

@@ -0,0 +1,48 @@
+import argparse
+import glob
+
+def main():
+    parser = argparse.ArgumentParser(description="cat with -n and -b options")
+    parser.add_argument("-n", action="store_true", help="Number all output lines")
+    parser.add_argument("-b", action="store_true", help="Number non-blank lines (overrides -n)")
+    parser.add_argument("files", nargs="+", help="Files to read (supports *.txt)")
+    args = parser.parse_args()
+
+    # -b overrides -n
+    number_all = args.n
+    number_nonblank = args.b
+    if number_all and number_nonblank:
+        number_all = False
+
+    # Expand wildcard patterns (e.g. *.txt)
+    file_list = []
+    for pattern in args.files:
+        matched_files = glob.glob(pattern)
+        if matched_files:
+            file_list.extend(matched_files)
+        else:
+            file_list.append(pattern)
+
+    # Print contents of each file
+    line_number = 1
+    for filename in file_list:
+        try:
+            with open(filename, "r") as f:
+                for line in f:
+                    text = line.rstrip("\n")
+                    if number_nonblank:
+                        if text.strip():  # only number non-blank lines
+                            print(f"{line_number:6}\t{text}")
+                            line_number += 1
+                        else:
+                            print()
+                    elif number_all:
+                        print(f"{line_number:6}\t{text}")
+                        line_number += 1
+                    else:
+                        print(text)
+        except FileNotFoundError:
+            print(f"cat: {filename}: No such file or directory")
+
+if __name__ == "__main__":
+    main()

implement-shell-tools/ls/ls.py

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+import argparse
+import os
+
+parser = argparse.ArgumentParser(description="Display one file per line from ls directory")
+
+parser.add_argument("-1", dest="one", action="store_true", help="List one file per line")
+parser.add_argument("-a", action="store_true", help="Include hidden files (those starting with .)")
+parser.add_argument("path", nargs="?", default=".", help="The directory to list (default: current directory)")
+
+args = parser.parse_args()
+
+
+files = sorted(os.listdir(args.path))
+
+
+if not args.a:
+    files = [f for f in files if not f.startswith(".")]
+
+if args.one:
+    for f in files:
+        print(f)
+else:
+    print("  ".join(files))

implement-shell-tools/wc/wc.py

@@ -0,0 +1,78 @@
+import argparse
+import glob
+
+def count_file(filename):
+    line_count = 0
+    word_count = 0
+    byte_count = 0
+
+    try:
+        with open(filename, "rb") as f:
+            content = f.read()
+            byte_count = len(content)
+            text = content.decode("utf-8", errors="replace")
+            lines = text.splitlines()
+            line_count = len(lines)
+            word_count = sum(len(line.split()) for line in lines)
+
+        return (line_count, word_count, byte_count)
+    except FileNotFoundError:
+        print(f"wc: {filename}: No such file or directory")
+        return None
+
+def main():
+    parser = argparse.ArgumentParser(description="Python version of wc")
+    parser.add_argument("-l", action="store_true", help="Count lines")
+    parser.add_argument("-w", action="store_true", help="Count words")
+    parser.add_argument("-c", action="store_true", help="Count bytes")
+    parser.add_argument("files", nargs="+", help="Files to read (supports wildcards)")
+    args = parser.parse_args()
+
+    # If no flag is given, show all
+    show_lines = args.l
+    show_words = args.w
+    show_bytes = args.c
+    if not (show_lines or show_words or show_bytes):
+        show_lines = show_words = show_bytes = True
+
+    file_list = []
+    for pattern in args.files:
+        matched = glob.glob(pattern)
+        if matched:
+            file_list.extend(matched)
+        else:
+            file_list.append(pattern)
+
+    total_lines = total_words = total_bytes = 0
+    for filename in file_list:
+        result = count_file(filename)
+        if result is None:
+            continue
+        lines, words, bytes_ = result
+        total_lines += lines
+        total_words += words
+        total_bytes += bytes_
+
+        output = []
+        if show_lines:
+            output.append(f"{lines:7}")
+        if show_words:
+            output.append(f"{words:7}")
+        if show_bytes:
+            output.append(f"{bytes_:7}")
+        output.append(filename)
+        print(" ".join(output))
+
+    if len(file_list) > 1:
+        output = []
+        if show_lines:
+            output.append(f"{total_lines:7}")
+        if show_words:
+            output.append(f"{total_words:7}")
+        if show_bytes:
+            output.append(f"{total_bytes:7}")
+        output.append("total")
+        print(" ".join(output))
+
+if __name__ == "__main__":
+    main()