London | Ameneh Keshavarz | Implement-shell-tools| WEEK 4

.gitignore

@@ -1 +1,2 @@
 node_modules
+venv/

implement-shell-tools/cat/cat.py

@@ -0,0 +1,57 @@
+import argparse
+import sys
+
+def setup_arguments():
+    parser = argparse.ArgumentParser(
+        prog="cat",
+        description="Concatenate and display files, optionally numbering lines."
+    )
+
+    group = parser.add_mutually_exclusive_group()
+    group.add_argument("-n", "--number", action="store_true", help="Number all output lines, starting at 1.")
+    group.add_argument("-b", "--number-nonblank", action="store_true", help="Number non-empty output lines, starting at 1.")
+    parser.add_argument("paths", nargs='+', help="Files to read ('-' for stdin).")
+
+    return parser.parse_args()
+
+def read_file_content(path):
+    try:
+        if path == "-":
+            return sys.stdin.read()
+        with open(path, 'r', encoding='utf-8') as f:
+            return f.read()
+    except Exception as e:
+        print(f"Error reading {path}: {e}", file=sys.stderr)
+        return ""
+
+def extract_content_lines(content):
+    return content.splitlines()
+
+def output_lines(lines, number_all, number_nonblank):
+    line_number = 1
+    for line in lines:
+        if number_all:
+            print(f"{line_number:6}\t{line}")
+            line_number += 1
+        elif number_nonblank:
+            if line.strip() != "":
+                print(f"{line_number:6}\t{line}")
+                line_number += 1
+            else:
+                print()
+        else:
+            print(line)
+
+def main():
+    args = setup_arguments()
+    all_lines = []
+
+    for path in args.paths:
+        content = read_file_content(path)
+        lines = extract_content_lines(content)
+        all_lines.extend(lines)
+
+    output_lines(all_lines, args.number, args.number_nonblank)
+
+if __name__ == "__main__":
+    main()

implement-shell-tools/ls/ls.py

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+import argparse
+import os
+
+def setup_arguments():
+    parser = argparse.ArgumentParser(
+        prog="custom_ls",
+        description="Lists contents of a directory"
+    )
+    parser.add_argument(
+        "path", nargs="?", default=".",
+        help="Path to the target directory (defaults to current)"
+    )
+    parser.add_argument(
+        "-1", dest="linewise", action="store_true",
+        help="Display one entry per line"
+    )
+    parser.add_argument(
+        "-a", dest="include_hidden", action="store_true",
+        help="Include hidden files in the output"
+    )
+    return parser.parse_args()
+
+def list_directory(path, show_hidden, one_per_line):
+    try:
+        items = os.listdir(path)
+    except FileNotFoundError:
+        print(f"Error: '{path}' not found.")
+        return
+    except NotADirectoryError:
+        print(f"Error: '{path}' is not a directory.")
+        return
+
+    entries = [
+        entry for entry in sorted(items)
+        if show_hidden or not entry.startswith(".")
+    ]
+
+    if one_per_line:
+        for entry in entries:
+            print(entry)
+    else:
+        print("  ".join(entries))
+
+def main():
+    args = setup_arguments()
+    list_directory(
+        path=args.path,
+        show_hidden=args.include_hidden,
+        one_per_line=args.linewise
+    )
+
+if __name__ == "__main__":
+    main()

implement-shell-tools/package.json

@@ -0,0 +1,5 @@
+{
+    "name": "py-cli-tools",
+    "version": "1.0.0"
+  }
+

implement-shell-tools/wc/wc.py

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+import argparse
+
+def setup_arguments():
+    parser = argparse.ArgumentParser(
+        prog="wordcount",
+        description="A simple wc clone that reads files and displays line, word, and character counts."
+    )
+
+    parser.add_argument("files", nargs='+', help="Files to analyze")
+    parser.add_argument("-l", "--lines", action="store_true", help="Count lines")
+    parser.add_argument("-w", "--words", action="store_true", help="Count words")
+    parser.add_argument("-c", "--chars", action="store_true", help="Count characters")
+
+    return parser.parse_args()
+
+def read_text_from_file(path):
+    with open(path, "r") as f:
+        return f.read()
+
+def count_lines(text):
+    return len(text.rstrip('\n').split('\n'))
+
+def count_words(text):
+    return len(text.split())
+
+def count_characters(text):
+    return len(text)
+
+def analyze_file(path):
+    data = read_text_from_file(path)
+    return {
+        "lines": count_lines(data),
+        "words": count_words(data),
+        "chars": count_characters(data)
+    }
+
+def show_counts(counts, path, opts):
+    if opts.lines:
+        print(counts["lines"], path)
+    elif opts.words:
+        print(counts["words"], path)
+    elif opts.chars:
+        print(counts["chars"], path)
+    else:
+        print(counts["lines"], counts["words"], counts["chars"], path)
+
+def show_total(all_counts, opts):
+    total = {
+        "lines": sum(c["lines"] for c in all_counts),
+        "words": sum(c["words"] for c in all_counts),
+        "chars": sum(c["chars"] for c in all_counts)
+    }
+    if opts.lines:
+        print(total["lines"], "total")
+    elif opts.words:
+        print(total["words"], "total")
+    elif opts.chars:
+        print(total["chars"], "total")
+    else:
+        print(total["lines"], total["words"], total["chars"], "total")
+
+def main():
+    options = setup_arguments()
+    all_results = []
+
+    for file in options.files:
+        result = analyze_file(file)
+        all_results.append(result)
+        show_counts(result, file, options)
+
+    if len(options.files) > 1:
+        show_total(all_results, options)
+
+if __name__ == "__main__":
+    main()