Manchester | 25-SDC-Nov | Geraldine Edwards | Sprint 4 | Implement Shell Tools Python

implement-shell-tools/cat/cat.py

@@ -0,0 +1,44 @@
+import argparse
+
+
+parser = argparse.ArgumentParser(
+    prog="cat",
+    description="An alternative to the 'cat' command",
+)
+
+parser.add_argument("files", nargs="+", help="The file(s) to process")
+parser.add_argument("-n", "--number", action="store_true", help="Number all output lines")
+parser.add_argument("-b", "--number-nonblank", action="store_true", help="Number non-blank output lines")
+
+args = parser.parse_args()
+
+
+
+def print_line(line, padding_width, line_number=None):
+    """Helper function to print a line with optional line numbering."""
+    if line_number is not None:
+        print(f"{str(line_number).rjust(padding_width)}  {line}")
+    else:
+        print(line)
+
+line_number = 1 
+padding_width = 6  
+
+for file in args.files:
+    with open(file, "r") as f:
+        # read the content and split the lines ready to process as needed
+        content = f.read().splitlines()
+
+    for line in content:
+        # use .strip() to remove leading and trailing whitespace or /n
+        if args.number_nonblank and line.strip():
+            # number non-blank lines only
+            print_line(line, padding_width, line_number)
+            line_number += 1
+        elif args.number:
+            # number all lines
+            print_line(line, padding_width, line_number)
+            line_number += 1
+        else:
+            # no flags
+            print_line(line, padding_width)

implement-shell-tools/ls/ls.py

@@ -0,0 +1,47 @@
+import os
+import argparse
+import locale
+
+
+#set locale to the machine default setting
+locale.setlocale(locale.LC_ALL, '')
+
+
+parser = argparse.ArgumentParser(
+    prog="ls",
+    description="An alternative to the 'ls' command",
+)
+
+parser.add_argument("directory", nargs="?", default=".", help="The directory to list (defaults to the current directory)")
+parser.add_argument("-1", "--single-column", action="store_true", help="List all files, one per line")
+parser.add_argument("-a", "--all", action="store_true", help="Include hidden files (those starting with .) in the listing")
+
+args = parser.parse_args()
+
+# check if path exists 
+if not os.path.exists(args.directory):
+    print(f"ls: cannot access '${args.directory}': No such file or directory")
+    exit(1)
+
+# check if path is a directory
+if os.path.isdir(args.directory):
+    entries = os.listdir(args.directory)
+
+    # if -a flag set
+    if args.all:
+        entries.extend(['.', '..'])
+
+    # filter hidden files if -a (all) flag not set
+    if not args.all:
+        entries = [entry for entry in entries if not entry.startswith(".")]
+
+    # sort the entries using locale-aware comparison
+    entries.sort(key =locale.strxfrm)
+
+    # print entries
+    if args.single_column:
+        for entry in entries:
+            print(entry)
+    else:
+        print("  ".join(entries))
+

implement-shell-tools/wc/wc.py

@@ -0,0 +1,68 @@
+import argparse
+import locale
+
+
+#set locale to the machine default setting
+locale.setlocale(locale.LC_ALL, '')
+
+parser = argparse.ArgumentParser(
+    prog="wc",
+    description="An alternative to the 'wc' command",
+)
+parser.add_argument("files", nargs="+", help="The file(s) to process")
+parser.add_argument("-l", "--lines", action="store_true", help="Print the newline counts")
+parser.add_argument("-w", "--words", action="store_true", help="Print the word counts")
+parser.add_argument("-c", "--bytes", action="store_true", help="Print the byte counts")
+
+args = parser.parse_args()
+
+# when no specific flags are set
+no_flags = not (args.lines or args.words or args.bytes)
+
+totals = {"lines": 0, "words": 0, "bytes": 0}
+
+def calculate_counts(content):
+    # returns a count object
+    return {
+        "lines": content.count('\n') + (1 if content and not content.endswith('\n') else 0), # count lines by '\n'; add 1 if last line has no newline to match real wc command behavior"
+        "words": len(content.split()),
+        "bytes": len(content.encode('utf-8')),
+    }
+
+
+def print_counts(counts, file):
+    parts = []
+    # map flag args to the keys in the count object
+    flag_arg_to_key = {
+        "lines": args.lines,
+        "words": args.words,
+        "bytes": args.bytes
+    }
+
+    PADDING = 3
+
+    for key, flag in flag_arg_to_key.items():
+        if no_flags or flag:
+            # apply padding only when no_flags is True
+            padded_output = f"{counts[key]:>{PADDING}}" if no_flags else str(counts[key])
+            parts.append(padded_output)
+    parts.append(file)
+    print(" ".join(parts))
+
+
+for file in args.files:
+    try: 
+        with open(file, "r") as f:
+            # read the content and split the lines ready to process as needed
+            content = f.read()  
+            counts = calculate_counts(content)
+        # update totals object with values from count object
+        for key in totals:
+            totals[key] += counts[key]
+        print_counts(counts, file)    
+    except FileNotFoundError:
+        print(f"wc: {file}: No such file or directory found") 
+
+# Print totals if more than one file
+if len(args.files) > 1:
+    print_counts(totals, "total")