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

implement-shell-tools/cat/cat.py

@@ -0,0 +1,57 @@
+# in built module
+import sys
+
+args = sys.argv[1:]
+
+flag = ""
+file_paths = []
+
+
+# Check if the first argument is a flag like -n or -b
+if args and args[0].startswith("-"):
+    flag = args[0]
+    file_paths = args[1:]
+else:
+    file_paths = args
+
+
+# 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
+
+sys.stdout.write("\n".join(lines))

implement-shell-tools/ls/ls.py

@@ -0,0 +1,48 @@
+# Access command-line arguments from the terminal
+import sys
+
+# Work with the operating system (files and directories)
+import os
+
+# Get command-line arguments
+args = sys.argv[1:]
+
+flags = []
+paths = []
+
+
+# Separate flags and paths
+for arg in args:
+    if arg.startswith("-"):
+        flags.append(arg)
+    else:
+        paths.append(arg)
+
+
+# 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 +1,74 @@
+import sys
+
+args = sys.argv[1:]
+
+flags = []
+paths = []
+
+# Separate flags and paths
+for arg in args:
+    if arg.startswith("-"):
+        flags.append(arg)
+    else:
+        paths.append(arg)
+
+
+total_lines = 0
+total_words = 0
+total_chars = 0
+
+
+for file in paths:
+
+    # Read file as bytes
+    with open(file, "rb") as f:
+        content = f.read()
+
+    # Count
+    lines = content.count(b"\n")
+    words = len(content.split())
+    chars = len(content)
+
+    # Output for this file
+    output = []
+
+    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)
+
+    print(*output, file)
+
+    # Add to totals
+    total_lines += lines
+    total_words += words
+    total_chars += chars
+
+
+# Print total only when multiple files
+if len(paths) > 1:
+
+    total_output = []
+
+    if len(flags) == 0:
+        total_output = [total_lines, total_words, total_chars]
+
+    else:
+        if "-l" in flags:
+            total_output.append(total_lines)
+
+        if "-w" in flags:
+            total_output.append(total_words)
+
+        if "-c" in flags:
+            total_output.append(total_chars)
+
+    print(*total_output, "total")