LONDON SDC | Anna Fedyna | Module-Tools | Week 4 | Implement Shell Tools in Python

implement-shell-tools/cat/cat.py

@@ -0,0 +1,29 @@
+import argparse
+
+parser = argparse.ArgumentParser(
+                    prog='Cat Command',
+                    description='Display and concatenate files contents')
+
+parser.add_argument("-n", help="Number the output lines, starting at 1.", default = None, action="store_true")
+parser.add_argument("-b", help="Number the non-blank output lines, starting at 1.", default = None, action="store_true")
+parser.add_argument("paths", nargs="+", help="The file to search")
+
+args = parser.parse_args()
+
+for path in args.paths:
+    try:
+        with open(path, "r") as f:
+            content = f.read()
+        if args.n or args.b :
+            counter = 1
+            arr = content.split('\n')[:-1]
+            for line in arr:
+                if args.b and not line:
+                    print(line)
+                    continue
+                print(counter, line)
+                counter += 1
+    except FileNotFoundError:
+        print(f"Error: File '{path}' not found.")
+    except Exception as e:
+        print(f"An error occurred: {e}")

implement-shell-tools/ls/ls.py

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+import argparse
+import os 
+
+parser = argparse.ArgumentParser(
+                    prog='ls command',
+                    description='list directory contents')
+
+parser.add_argument("-1", "--one", help="Force output to be one entry per line.", default = None, action="store_true")
+parser.add_argument("-a", help="Include directory entries whose names begin with a dot (.).", default = None, action="store_true")
+parser.add_argument("paths", nargs="*", help="The file to search")
+
+args = parser.parse_args()
+cwd = os.getcwd()
+
+def list_docs(dir_to_procccess):
+    try:
+        documents = [document for document in os.listdir(dir_to_procccess)]
+        doc_to_output = []
+        for doc in documents:
+                if not args.a and doc.startswith("."): 
+                    continue
+                else:
+                    doc_to_output.append(doc)
+        doc_to_output.sort()
+        if args.one:
+            for doc in doc_to_output:
+                print(doc)
+        else:
+            print(' '.join(doc_to_output))
+    except FileNotFoundError:
+        print(f"Error: Directory '{dir_to_procccess}' not found.")
+    except NotADirectoryError:
+        print(f"Error: '{dir_to_procccess}' is not a directory.")
+    except Exception as e:
+        print(f"An unexpected error occurred: {e}")
+
+if args.paths:
+    for directory in args.paths:
+        try:
+            dir_to_procccess = os.path.join(cwd, directory)
+            list_docs(dir_to_procccess)
+        except Exception as e:
+            print(f"An unexpected error occurred: {e}")
+else:
+    list_docs(cwd)

implement-shell-tools/wc/wc.py

@@ -0,0 +1,72 @@
+import argparse
+import os 
+import re
+
+parser = argparse.ArgumentParser(
+                    prog='wc command',
+                    description='word, line, character, and byte count')
+
+parser.add_argument("-c", "--bytes", help="The number of bytes in each input file is written to the standard output.", default = None, action="store_true")
+parser.add_argument("-l", "--lines", help="The number of lines in each input file is written to the standard output.", default = None, action="store_true")
+parser.add_argument("-w", "--words", help="The number of words in each input file is written to the standard output.", default = None, action="store_true")
+parser.add_argument("paths", nargs="+", help="The file to search")
+
+args = parser.parse_args()
+cwd = os.getcwd()
+
+
+def count_lines(content):
+    return len(content.splitlines())
+
+def count_words(content):
+    return len(re.findall("[a-zA-Z\-\.'/]+", content))
+
+def count_bytes(content):
+    return len(content.encode('utf-8'))
+
+def process_file_content(content, path):
+    if not args.lines and not args.words and not args.bytes:
+        global no_options
+        no_options = True
+        lines_in_file = count_lines(content)
+        words_in_file = count_words(content)
+        bytes_in_file = count_bytes(content)
+        print(lines_in_file, words_in_file, bytes_in_file, path)
+        return {'lines': lines_in_file, 'words':words_in_file, 'bytes':bytes_in_file}
+    output = {}
+    if args.lines:
+        output['lines'] = count_lines(content)
+    if args.words:
+        output['words'] = count_words(content)
+    if args.bytes:
+        output['bytes'] = count_bytes(content)
+    print(' '.join([ str(val) for val in output.values()]), path)
+    return output
+
+total_lines, total_words, total_bytes = 0, 0, 0
+for path in args.paths:
+    try:
+        file_path_to_procccess = os.path.join(cwd, path)
+        if os.path.isfile(file_path_to_procccess) : 
+            with open(file_path_to_procccess, 'r') as f:
+                file_content = f.read()
+                dict_output = process_file_content(file_content, path)
+                total_lines += dict_output['lines'] if args.lines or no_options else 0
+                total_words += dict_output['words'] if args.words or no_options else 0
+                total_bytes += dict_output['bytes'] if args.bytes or no_options else 0
+        elif os.path.isdir(file_path_to_procccess):
+            print(f"{path}: Is a directory")
+    except FileNotFoundError:
+        print(f"Error: File '{file_path_to_procccess}' not found.")
+    except Exception as e:
+            print(f"An unexpected error occurred: {e}")
+
+if len(args.paths) > 1:
+    if no_options:
+        print(total_lines, total_words, total_bytes, 'total')
+    else:
+        total_output_line = []
+        if args.lines: total_output_line.append(str(total_lines))
+        if args.words: total_output_line.append(str(total_words))
+        if args.bytes: total_output_line.append(str(total_bytes))
+        print(' '.join(total_output_line), 'total')