ZA | 25-SDC-July | Luke Manyamazi | Sprint 4 | Python Implement Shell Tools Exercises

implement-shell-tools/cat/cat.py

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+import argparse
+import sys
+from enum import Enum
+
+class Numbering(Enum):
+    NONE = 0
+    ALL = 1
+    NONEMPTY = 2
+
+def print_numbered_line(line, line_number, pad=6):
+    print(f"{line_number:{pad}}\t{line}", end='')
+    return line_number + 1
+
+def cat(filepath, numbering, start_line):
+    line_number = start_line
+    try:
+        with open(filepath) as f:
+            for line in f:
+                if numbering == Numbering.NONEMPTY:
+                    if line.strip():
+                        line_number = print_numbered_line(line, line_number)
+                    else:
+                        print(line, end='')
+                elif numbering == Numbering.ALL:
+                    line_number = print_numbered_line(line, line_number)
+                else:
+                    print(line, end='')
+    except FileNotFoundError:
+        print(
+            f"cat: {filepath}: No such file or directory",
+            file=sys.stderr
+        )
+    return line_number
+
+def main():
+    parser = argparse.ArgumentParser(
+        description="Concatenate files and print on the standard output."
+    )
+    parser.add_argument('-n', action='store_true', help='number all output lines')
+    parser.add_argument('-b', action='store_true', help='number non-empty output lines')
+    parser.add_argument('files', nargs='+', help='files to concatenate')
+    args = parser.parse_args()
+
+    if args.n and args.b:
+        parser.error("options -n and -b are mutually exclusive")
+    elif args.n:
+        numbering = Numbering.ALL
+    elif args.b:
+        numbering = Numbering.NONEMPTY
+    else:
+        numbering = Numbering.NONE
+
+    line_number = 1
+
+    for file in args.files:
+        line_number = cat(file, numbering=numbering, start_line=line_number)
+
+if __name__ == "__main__":
+    main()

implement-shell-tools/ls/ls.py

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+import os
+import sys
+import argparse
+
+def ls(path, one_column, show_hidden):
+    """List files in a directory, optionally in one column or including hidden files."""
+    try:
+        if os.path.isfile(path):
+            print(os.path.basename(path))
+            return
+
+        files = os.listdir(path)
+
+        if show_hidden:
+            files = ['.', '..'] + files
+        else:
+            files = [f for f in files if not f.startswith('.')]
+
+        files.sort()
+
+        if one_column:
+            print(*files, sep='\n')
+        else:
+            print(*files)
+
+    except FileNotFoundError:
+        print(
+            f"ls: cannot access '{path}': No such file or directory",
+            file=sys.stderr
+        )
+    except NotADirectoryError:
+        print(
+            f"ls: cannot access '{path}': Not a directory",
+            file=sys.stderr
+        )
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('-1', dest='one_column', action='store_true', help='list one file per line')
+    parser.add_argument('-a', action='store_true', help='show hidden files')
+    parser.add_argument('path', nargs='?', default='.', help='directory to list')
+    args = parser.parse_args()
+
+    ls(args.path, args.one_column, args.a)
+
+if __name__ == "__main__":
+    main()

implement-shell-tools/wc/wc.py

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+import argparse
+import sys
+
+def wc(path, count_lines, count_words, count_bytes):
+    """Count lines, words, and bytes for a single file."""
+    try:
+        with open(path, 'r') as f:
+            content = f.read()
+
+        lines = content.splitlines()
+        words = content.split()
+
+        line_count = len(lines)
+        word_count = len(words)
+        byte_count = len(content.encode('utf-8'))
+
+        if not any([count_lines, count_words, count_bytes]):
+            count_lines = True
+            count_words = True
+            count_bytes = True
+
+        parts = []
+
+        if count_lines:
+            parts.append(str(line_count))
+
+        if count_words:
+            parts.append(str(word_count))
+
+        if count_bytes:
+            parts.append(str(byte_count))
+
+        print(' '.join(parts), path)
+
+        return line_count, word_count, byte_count
+
+    except FileNotFoundError:
+        print(
+            f"wc: {path}: No such file or directory",
+            file=sys.stderr
+        )
+        return (0, 0, 0)
+
+    except IsADirectoryError:
+        print(
+            f"wc: {path}: Is a directory",
+            file=sys.stderr
+        )
+        return (0, 0, 0)
+
+def main():
+    parser = argparse.ArgumentParser()
+    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('paths', nargs='+', help='Files to count')
+    args = parser.parse_args()
+
+    total_lines = 0
+    total_words = 0
+    total_bytes = 0
+
+    multiple_files = len(args.paths) > 1
+    show_all = not any([args.l, args.w, args.c])
+
+    for path in args.paths:
+        l, w, b = wc(path, args.l, args.w, args.c)
+        total_lines += l
+        total_words += w
+        total_bytes += b
+
+    if multiple_files:
+        parts = []
+
+        if args.l or show_all:
+            parts.append(str(total_lines))
+
+        if args.w or show_all:
+            parts.append(str(total_words))
+
+        if args.c or show_all:
+            parts.append(str(total_bytes))
+
+        print(' '.join(parts), 'total')
+
+if __name__ == "__main__":
+    main()