London | 25-SDC-July | Andrei Filippov | Sprint 4 | Implement shell tools in Python

implement-shell-tools/cat/cat.py

@@ -0,0 +1,38 @@
+import argparse
+import os
+
+parser = argparse.ArgumentParser(
+    prog="cat",
+    description="Concatenate and print files",
+)
+
+parser.add_argument(
+    "-n", action="store_true", help="Number the output lines, starting at 1"
+)
+parser.add_argument(
+    "-b", action="store_true", help="Number the non-blank output lines, starting at 1"
+)
+parser.add_argument("path", nargs="+", help="The path to search")
+
+args = parser.parse_args()
+for path in args.path:
+    if os.path.isfile(path):
+        with open(path) as file:
+            lines = file.readlines()
+            line_num = 1
+            for line in lines:
+                lin = line.rstrip("\n")
+                if args.b:
+                    if lin == "":
+                        print()
+                    else:
+                        print(str(line_num).rjust(6), lin)
+                        line_num += 1
+                elif args.n:
+                    print(str(line_num).rjust(6), "", lin)
+                    line_num += 1
+
+                else:
+                    print(lin)
+    else:
+        print(f"cat: {path}: Is a directory")

implement-shell-tools/ls/ls.py

@@ -0,0 +1,41 @@
+import os
+import argparse
+
+parser = argparse.ArgumentParser(
+    prog="ls",
+    description="list directory contents",
+)
+
+parser.add_argument("-1",dest="one",action='store_true', help="list one file per line")
+parser.add_argument("-a", action='store_true', help="Used to list all files, including hidden files, in the current directory")
+parser.add_argument("path", nargs="?", default=".", help="The path to search")
+
+args = parser.parse_args()
+
+def arguments_proceeding(files):
+    data_to_proceed = files
+
+    if args.a:
+        data_to_proceed = [f for f in files]
+        data_to_proceed.sort()
+        data_to_proceed.insert(0, "..")
+        data_to_proceed.insert(0, ".")
+    else:
+        data_to_proceed = [f for f in files if not f.startswith('.')]
+    data_to_proceed.sort(key=str.lower)
+    if args.one:
+        output = [f for f in data_to_proceed]
+        for f in output:
+            print(f)
+    else: 
+        print("         ".join(data_to_proceed))
+
+
+def path_proceeding(path_argument):
+    if os.path.isfile(path_argument):
+        print(path_argument)
+    elif os.path.isdir(path_argument):
+        files = os.listdir(path_argument)
+        arguments_proceeding(files)
+
+path_proceeding(args.path)

implement-shell-tools/wc/wc.py

@@ -0,0 +1,75 @@
+import os
+import argparse
+
+parser = argparse.ArgumentParser(
+    prog="wc",
+    description="Counts words in a file that contain a particular character",
+)
+
+parser.add_argument(
+    "-l",
+    action="store_true",
+    help="The number of lines in each input file is written to the standard output.",
+)
+parser.add_argument(
+    "-w",
+    action="store_true",
+    help="The number of words in each input file is written to the standard output.",
+)
+parser.add_argument(
+    "-c",
+    action="store_true",
+    help="The number of bytes in each input file is written to the standard output.",
+)
+parser.add_argument("path", nargs="+", help="The path to search")
+
+args = parser.parse_args()
+
+if not args.w and not args.c and not args.l:
+    args.w = args.c = args.l = True
+per_file_totals = []
+output = []
+column_widths = []
+for path in args.path:
+    output_for_one_file = []
+    if args.l or args.w:
+        with open(path) as file:
+            lines = file.readlines()
+            # lines count
+            if args.l:
+                num_lines = len(lines)
+                output_for_one_file.append(num_lines)
+            # word count
+            if args.w:
+                word_count = 0
+                for line in lines:
+                    lin = line.rstrip()
+                    wds = lin.split()
+                    word_count += len(wds)
+
+                output_for_one_file.append(word_count)
+
+    if args.c:
+        file_size = os.path.getsize(path)
+        output_for_one_file.append(file_size)
+
+    if len(args.path) > 1:
+        per_file_totals.append(output_for_one_file.copy())
+    output_for_one_file.append(path)
+    output.append(output_for_one_file)
+if len(args.path) > 1:
+    total_results = [sum(i) for i in zip(*per_file_totals)]
+    total_results.append("total")
+    output.append(total_results)
+
+    num_cols = len(total_results) - 1
+    column_widths = [len(str(total_results[i])) for i in range(num_cols)]
+elif len(args.path) == 1:
+    num_cols = len(output[0]) - 1
+    column_widths = [len(str([output[0][i]])) for i in range(num_cols)]
+for row in output:
+    line_parts = []
+    for i in range(num_cols):
+        # Right-align with 1 space padding (like wc)
+        line_parts.append(str(row[i]).rjust(column_widths[i] + 6))
+    print("".join(line_parts), row[-1])