London | 26-SDC-Mar | Jamal Laqdiem | Sprint 4 | Implement Shell Tools In Python

.gitignore

@@ -1,2 +1,3 @@
 node_modules
+.venv
 testoutput.txt

implement-shell-tools/cat/cat.py

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+import sys
+import argparse
+
+# 1. Set up argparse to handle flags and files
+parser = argparse.ArgumentParser(description="A simple Python implementation of the cat command.")
+
+# Add the optional flags (-n and -b)
+parser.add_argument("-n", action="store_true", help="Number all output lines")
+parser.add_argument("-b", action="store_true", help="Number nonempty output lines, overrides -n")
+
+# Add the files argument (nargs="*" means it accepts 0 or more files)
+parser.add_argument("files", nargs="*", help="Files to read")
+
+# Parse the arguments
+args = parser.parse_args()
+
+show_all_numbers = args.n
+show_non_blank_numbers = args.b
+files = args.files
+
+
+if not files:
+    print("Usage: python3 cat.py [-n] [-b] <filenames>")
+    sys.exit()
+
+line_count = 1
+# 3. Process each file 
+for filename in files:
+    try:
+        with open(filename, "r") as file:
+            for line in file:
+                # Logic for -b 
+                if show_non_blank_numbers:
+                    if line.strip(): # If line is not empty
+                        print(f"{line_count:>6}\t{line}", end="")
+                        line_count += 1
+                    else:
+                        # Standard cat no flags
+                        print(line, end="")
+
+                # Logic for -n 
+                elif show_all_numbers:
+                    print(f"{line_count:>6}\t{line}", end="")
+                    line_count += 1
+
+                # Standard cat no flags
+                else:
+                    print(line, end="")
+
+    # throw clear errors                
+    except FileNotFoundError:
+        print(f"Error: {filename}: No such file or directory")
+    except IsADirectoryError:
+        print(f"Error: {filename}: Is a directory")

implement-shell-tools/ls/ls.py

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+import os
+import sys
+import argparse
+
+# 1. Set up argparse to handle the ls flags
+parser = argparse.ArgumentParser(description="A simple Python implementation of the ls command.")
+
+# Add the -a and -1 flags
+parser.add_argument("-a", action="store_true", help="Do not ignore entries starting with .")
+parser.add_argument("-1", action="store_true",dest="one_column", help="List one file per line")
+
+# Add the path argument (nargs="?" means it's optional, default is current directory ".")
+parser.add_argument("path", nargs="?", default=".", help="Directory path to list")
+
+# Parse the arguments
+args = parser.parse_args()
+
+# 2. rename back  variables
+show_all = args.a
+one_column = args.one_column
+path = args.path
+
+try:
+    # Get directory contents
+    entries = os.listdir(path)
+
+    # Handle the -a flag 
+    if show_all:
+        entries.extend([".", ".."])
+
+    # 5. Sort alphabetically
+    entries.sort()
+
+    # Printing Logic 
+    for entry in entries:
+        # Skip hidden files unless -a is passed
+        if not show_all and entry.startswith("."):
+            continue
+
+        if one_column:
+            # -1 flag: Print vertically
+            print(entry)
+        else:
+            # Standard: Print horizontally with spaces
+            print(entry, end="  ")
+
+    #  newline only if we not print horizontally
+    if not one_column:
+        print()
+
+except FileNotFoundError:
+    print(f"ls: cannot access '{path}': No such file or directory")
+except NotADirectoryError:
+    # if a file  ls just prints the filename
+    print(path)

implement-shell-tools/wc/wc.py

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+import sys
+import os
+import argparse
+
+# 1. Set up argparse to handle the wc flags
+parser = argparse.ArgumentParser(description="A simple Python implementation of the wc command.")
+
+# Add the optional flags (-l, -w, -c)
+parser.add_argument("-l", action="store_true", help="Print the newline counts")
+parser.add_argument("-w", action="store_true", help="Print the word counts")
+parser.add_argument("-c", action="store_true", help="Print the byte counts")
+
+# Add the files argument (nargs="*" means it accepts 0 or more files)
+parser.add_argument("files", nargs="*", help="Files to process")
+
+# Parse the arguments
+args = parser.parse_args()
+
+# 2. Rename back the variables
+show_lines = args.l
+show_words = args.w
+show_chars = args.c
+files = args.files
+
+# If no flags then show all.
+show_all = not (show_lines or show_words or show_chars)
+
+
+# Total counters
+total_l, total_w, total_c = 0, 0, 0
+
+for filename in files:
+    try:
+        with open(filename, 'r') as f:
+            lines = f.readlines()
+
+            # files calculation
+            l_count = len(lines)
+            w_count = sum(len(line.split()) for line in lines)
+            #  os.path.getsize for bytes, in .js I used const bytes = Buffer.byteLength(content);
+            c_count = os.path.getsize(filename)
+
+            # Update totals
+            total_l += l_count
+            total_w += w_count
+            total_c += c_count
+
+            # Printing Logic
+            output = []
+            if show_lines or show_all: output.append(f"{l_count:>8}")
+            if show_words or show_all: output.append(f"{w_count:>8}")
+            if show_chars or show_all: output.append(f"{c_count:>8}")
+
+            print(f"{''.join(output)} {filename}")
+
+    except FileNotFoundError:
+        print(f"wc: {filename}: No such file or directory")
+    except IsADirectoryError:
+        print(f"wc: {filename}: Is a directory")
+        print(f"{'0':>8} {'0':>8} {'0':>8} {filename}")
+
+# Print Total if there were multiple files
+if len(files) > 1:
+    output_total = []
+    if show_lines or show_all: output_total.append(f"{total_l:>8}")
+    if show_words or show_all: output_total.append(f"{total_w:>8}")
+    if show_chars or show_all: output_total.append(f"{total_c:>8}")
+    print(f"{''.join(output_total)} total")