London | 26-jul-SDC | Shaghayegh far| Sprint 4 | Implement shell tools with python

implement-shell-tools/cat/cat.py

@@ -0,0 +1,43 @@
+import sys
+
+# Check if the user used a flag
+if len(sys.argv) > 1 and sys.argv[1] == "-n":
+
+    # Start from the second argument because the first is "-n"
+    for filename in sys.argv[2:]:
+
+        with open(filename, "r") as file:
+
+            line_number = 1
+
+            for line in file:
+                print(f"{line_number} {line}", end="")
+                line_number += 1
+
+
+elif len(sys.argv) > 1 and sys.argv[1] == "-b":
+
+    # Start from the second argument because the first is "-b"
+    for filename in sys.argv[2:]:
+
+        with open(filename, "r") as file:
+
+            line_number = 1
+
+            for line in file:
+
+                # Only number non-empty lines
+                if line.strip() == "":
+                    print(line, end="")
+                else:
+                    print(f"{line_number} {line}", end="")
+                    line_number += 1
+
+
+else:
+
+    # No flag, just print every file
+    for filename in sys.argv[1:]:
+
+        with open(filename, "r") as file:
+            print(file.read(), end="")

implement-shell-tools/ls/ls.py

@@ -0,0 +1,65 @@
+import sys
+import os
+
+
+# Get arguments from the command line
+arguments = sys.argv[1:]
+
+
+# Check if -1 flag exists
+show_one_per_line = False
+
+if "-1" in arguments:
+    show_one_per_line = True
+    arguments.remove("-1")
+
+
+# Check if -a flag exists
+show_all_files = False
+
+if "-a" in arguments:
+    show_all_files = True
+    arguments.remove("-a")
+
+
+# If no path is given, use current directory
+if len(arguments) == 0:
+    path = "."
+else:
+    path = arguments[0]
+
+
+# Check if the path exists
+if not os.path.exists(path):
+    print(f"ls: cannot access '{path}': No such file or directory")
+    sys.exit()
+
+
+# If the path is a file, just print the file name
+if os.path.isfile(path):
+    print(path)
+
+
+# If the path is a folder, list its contents
+else:
+
+    files = os.listdir(path)
+
+
+    # Remove hidden files unless -a was used
+    if not show_all_files:
+        files = [
+            file for file in files
+            if not file.startswith(".")
+        ]
+
+
+    # Print one file per line
+    if show_one_per_line:
+        for file in files:
+            print(file)
+
+
+    # Normal ls behaviour
+    else:
+        print("  ".join(files))

implement-shell-tools/wc/wc.py

@@ -0,0 +1,88 @@
+import sys
+
+
+# Get everything the user typed after wc.py
+arguments = sys.argv[1:]
+
+
+# These are our options
+count_lines = False
+count_words = False
+count_characters = False
+
+
+# Store file names here
+filenames = []
+
+
+# Check every argument
+for argument in arguments:
+
+    if argument == "-l":
+        count_lines = True
+
+    elif argument == "-w":
+        count_words = True
+
+    elif argument == "-c":
+        count_characters = True
+
+    else:
+        filenames.append(argument)
+
+
+
+# If the user did not give any flag,
+# show all counts like normal wc
+if (not count_lines 
+        and not count_words 
+        and not count_characters):
+
+    count_lines = True
+    count_words = True
+    count_characters = True
+
+
+
+# Go through every file
+for filename in filenames:
+
+    # Open the file
+    with open(filename, "r") as file:
+
+        # Read the whole file
+        content = file.read()
+
+
+        # Count lines
+        lines = len(content.splitlines())
+
+
+        # Count words
+        words = len(content.split())
+
+
+        # Count characters
+        characters = len(content)
+
+
+
+        # Prepare the answer
+        answer = ""
+
+
+        if count_lines:
+            answer += str(lines) + " "
+
+
+        if count_words:
+            answer += str(words) + " "
+
+
+        if count_characters:
+            answer += str(characters) + " "
+
+
+
+        # Print the result
+        print(answer + filename)