Implement ls, cat and wc in Python

Author: onurat

implement-shell-tools/cat/cat.py

@@ -0,0 +1,40 @@
+import sys
+
+args = sys.argv[1:]
+
+show_n = "-n" in args
+show_b = "-b" in args
+
+files = [arg for arg in args if not arg.startswith("-")]
+
+content = ""
+
+for file in files:
+    with open(file, "r") as f:
+        content += f.read()
+
+lines = content.split("\n")
+
+if lines and lines[-1] == "":
+    lines.pop()
+
+output = []
+
+if show_n:
+    for i, line in enumerate(lines, start=1):
+        output.append(f"{str(i).rjust(6)}  {line}")
+
+elif show_b:
+    count = 1
+
+    for line in lines:
+        if line != "":
+            output.append(f"{str(count).rjust(6)}  {line}")
+            count += 1
+        else:
+            output.append("")
+
+else:
+    output = lines
+
+print("\n".join(output))

implement-shell-tools/ls/ls.py

@@ -0,0 +1,22 @@
+import os
+import sys
+
+args = sys.argv[1:]
+
+show_all = "-a" in args
+
+directory = "."
+
+for arg in args:
+    if not arg.startswith("-"):
+        directory = arg
+
+files = sorted(os.listdir(directory))
+
+if show_all:
+    files = [".", ".."] + files
+else:
+    files = [file for file in files if not file.startswith(".")]
+
+for file in files:
+    print(file)

implement-shell-tools/wc/wc.py

@@ -0,0 +1,72 @@
+import sys
+
+args = sys.argv[1:]
+
+show_lines = "-l" in args
+show_words = "-w" in args
+show_bytes = "-c" in args
+
+files = [arg for arg in args if not arg.startswith("-")]
+
+def get_stats(text):
+    return {
+        "lines": text.count("\n"),
+        "words": len(text.split()),
+        "bytes": len(text.encode("utf-8"))
+    }
+
+def format_num(num):
+    return str(num).rjust(8)
+
+total_lines = 0
+total_words = 0
+total_bytes = 0
+
+for file in files:
+    with open(file, "r") as f:
+        content = f.read()
+
+    stats = get_stats(content)
+
+    total_lines += stats["lines"]
+    total_words += stats["words"]
+    total_bytes += stats["bytes"]
+
+    output = []
+
+    if show_lines:
+        output.append(format_num(stats["lines"]))
+    elif show_words:
+        output.append(format_num(stats["words"]))
+    elif show_bytes:
+        output.append(format_num(stats["bytes"]))
+    else:
+        output.extend([
+            format_num(stats["lines"]),
+            format_num(stats["words"]),
+            format_num(stats["bytes"])
+        ])
+
+    output.append(file)
+
+    print(" ".join(output))
+
+if len(files) > 1:
+    output = []
+
+    if show_lines:
+        output.append(format_num(total_lines))
+    elif show_words:
+        output.append(format_num(total_words))
+    elif show_bytes:
+        output.append(format_num(total_bytes))
+    else:
+        output.extend([
+            format_num(total_lines),
+            format_num(total_words),
+            format_num(total_bytes)
+        ])
+
+    output.append("total")
+
+    print(" ".join(output))