London | 26-Jul-SDC | Roman Sanaye | Sprint 4 | Implement shell tool in Python

implement-shell-tools/cat/cat.py

@@ -0,0 +1,61 @@
+# in built module
+import argparse
+
+parser = argparse.ArgumentParser()
+
+parser.add_argument("-n", action="store_true")
+parser.add_argument("-b", action="store_true")
+parser.add_argument("file_paths", nargs="+")
+
+args = parser.parse_args()
+
+flag = ""
+
+if args.n:
+    flag = "-n"
+elif args.b:
+    flag = "-b"
+
+file_paths = args.file_paths
+
+
+# Read all files and combine their contents into one string
+content = ""
+
+for file in file_paths:
+    with open(file, "r") as f:
+        content += f.read()
+
+
+# Split the file content into separate lines
+lines = content.splitlines()
+
+
+# Handle -n flag: add a number to every line
+if flag == "-n":
+    new_lines = []
+
+    for index, line in enumerate(lines):
+        new_lines.append(f"{index + 1}  {line}")
+
+    lines = new_lines
+
+
+# Handle -b flag: number only non-empty lines
+if flag == "-b":
+    line_number = 1
+    new_lines = []
+
+    for line in lines:
+        # Keep empty lines without adding numbers
+        if line.strip() == "":
+            new_lines.append(line)
+
+        # Add a number only to lines that contain text
+        else:
+            new_lines.append(f"{line_number}  {line}")
+            line_number += 1
+
+    lines = new_lines
+
+print("\n".join(lines))

implement-shell-tools/ls/ls.py

@@ -0,0 +1,49 @@
+import argparse
+import os
+
+# Set up command-line argument parser
+parser = argparse.ArgumentParser()
+
+# Add supported flags and file/directory paths
+parser.add_argument("-a", action="store_true")
+parser.add_argument("-1", dest="one", action="store_true")
+parser.add_argument("paths", nargs="*")
+
+# Parse the user's command-line arguments
+args = parser.parse_args()
+
+flags = []
+
+if args.a:
+    flags.append("-a")
+
+if args.one:
+    flags.append("-1")
+
+paths = args.paths
+
+
+# Use the current directory if no path is provided
+if not paths:
+    paths = ["."]
+
+
+# Process each path
+for path in paths:
+
+    # If the path is a file, print its name
+    if os.path.isfile(path):
+        print(path)
+
+    # If the path is a directory, get its contents
+    elif os.path.isdir(path):
+        contents = os.listdir(path)
+        if "-a" not in flags:
+            contents = [file for file in contents if not file.startswith(".")]
+        if "-1" in flags:
+            print("\n".join(contents))
+        else:
+            print(" ".join(contents))
+    # Handle invalid paths
+    else:
+        print(f"No such file or directory: {path}")

implement-shell-tools/wc/wc.py

@@ -0,0 +1,87 @@
+import argparse
+
+# Set up command-line argument parser
+parser = argparse.ArgumentParser()
+
+# Add supported flags
+parser.add_argument("-l", action="store_true")
+parser.add_argument("-w", action="store_true")
+parser.add_argument("-c", action="store_true")
+
+# Accept one or more file paths
+parser.add_argument("paths", nargs="+")
+
+# Parse the user's command-line arguments
+args = parser.parse_args()
+
+flags = []
+
+# Store selected flags for the existing logic
+if args.l:
+    flags.append("-l")
+
+if args.w:
+    flags.append("-w")
+
+if args.c:
+    flags.append("-c")
+
+paths = args.paths
+
+
+# Build the output based on the selected flags
+def get_output(lines, words, chars, flags):
+    output = []
+
+    # Show all counts when no flag is provided
+    if len(flags) == 0:
+        output = [lines, words, chars]
+
+    else:
+        if "-l" in flags:
+            output.append(lines)
+
+        if "-w" in flags:
+            output.append(words)
+
+        if "-c" in flags:
+            output.append(chars)
+
+    return output
+
+
+total_lines = 0
+total_words = 0
+total_chars = 0
+
+
+# Process each file
+for file in paths:
+
+    # Read file as bytes
+    with open(file, "rb") as f:
+        content = f.read()
+
+    # Count lines, words, and characters
+    lines = content.count(b"\n")
+    words = len(content.split())
+    chars = len(content)
+
+    # Create and print output for this file
+    output = get_output(lines, words, chars, flags)
+
+    # Print counts with aligned columns
+    print(" ".join(f"{value:3}" for value in output), file)
+
+    # Add this file's counts to the totals
+    total_lines += lines
+    total_words += words
+    total_chars += chars
+
+
+# Print total only when multiple files are provided
+if len(paths) > 1:
+    total_output = get_output(total_lines, total_words, total_chars, flags)
+
+    # Print aligned total
+    print(" ".join(f"{value:3}" for value in total_output), "total")