London | 26-SDC-Mar | Khilola Rustamova| Sprint 4 |Implement shell tools python

implement-shell-tools/cat/mycat.py

@@ -0,0 +1,72 @@
+#!/usr/bin/env python3
+
+import sys 
+
+def main():
+    args = sys.argv[1:]
+
+    if not args:
+        print("Usage: cat [-n|-b] file...", file=sys.stderr)
+        sys.exit(1)
+
+    number_mode = "none"
+    paths = []
+
+    for a in args:
+        if a == "-n":
+            number_mode = "all"
+        elif a == "-b":
+            number_mode = "non_empty"
+        else:
+            paths.append(a)
+
+
+
+    had_error = print_lines(
+        paths, 
+        number_mode=number_mode,
+        )
+
+    if had_error:
+        sys.exit(1)
+
+
+def read_lines(file):
+    with open(file, "r", encoding="utf-8") as f:
+        return f.readlines()
+
+def print_lines(files, number_mode="none"):
+    had_error = False
+    line_no = 1     
+    for file in files:
+        try:
+            lines = read_lines(file)
+        except FileNotFoundError:
+            print(f"cat: {file}: No such file or directory", file=sys.stderr)
+            had_error = True
+            continue
+
+        for line in lines:
+            is_empty = (line.strip() == "")
+
+            if number_mode == "non_empty":
+                if not is_empty:
+                    prefix = f"{line_no:6}\t"
+                    line_no += 1
+                else:
+                    prefix = "" 
+            elif number_mode=="all":
+                prefix = f"{line_no:6}\t"
+                line_no += 1
+            else:
+                prefix = ""
+
+            # avoid double newlines: line already includes '\n'
+            sys.stdout.write(prefix + line)
+
+    return had_error        
+
+if __name__ == "__main__":
+    main()      
+
+

implement-shell-tools/ls/my-ls.py

@@ -0,0 +1,65 @@
+#!/usr/bin/env python3
+
+import sys
+import os
+
+
+
+def main():
+    args = sys.argv[1:]
+
+    show_all = False
+    one_per_line = False
+    paths = []
+
+    for a in args:
+        if a == "-a":
+            show_all = True
+        elif a == "-1":
+            one_per_line = True    
+        else:
+            paths.append(a)
+
+    if not paths:
+        paths = ["."]
+
+    had_error = False
+
+    for path in paths:
+        if list_dir(
+            path, 
+            show_all=show_all, 
+            one_per_line=one_per_line,
+        ):
+            had_error = True
+
+    if had_error:
+       sys.exit(1)
+
+
+def list_dir(path, show_all=False, one_per_line=False):
+    try:
+        entries = os.listdir(path)
+    except FileNotFoundError:
+        print(f"ls: cannot access '{path}': No such file or directory", 
+              file=sys.stderr,
+        )
+        return True
+
+    entries = sorted(entries)
+
+    if show_all:
+        normal = sorted([e for e in entries if not e.startswith('.')])
+        hidden = sorted([e for e in entries if e.startswith('.')])
+
+        entries = [".", ".."] + normal + hidden
+    else:    
+        entries = sorted([e for e in entries if not e.startswith('.')])
+
+    for entry in entries:
+        print(entry)
+
+    return False
+
+if __name__ == "__main__":
+    main()

implement-shell-tools/wc/my-wc.py

@@ -0,0 +1,104 @@
+#!/usr/bin/env python3
+
+import sys
+
+
+def count_file(path):
+    with open(path, "rb") as f:
+        content = f.read()
+
+    byte_count = len(content)
+    text = content.decode("utf-8", errors="ignore")
+
+    line_count = text.count("\n")
+    word_count = len(text.split())
+
+    return line_count, word_count, byte_count
+
+
+
+def main():
+    args = sys.argv[1:]
+
+    show_l = False
+    show_w = False
+    show_c = False
+
+    paths = []
+
+
+    # parse args
+    for a in args:
+        if a == "-l":
+            show_l = True
+        elif a == "-w":
+            show_w = True
+        elif a == "-c":
+            show_c = True
+        else:
+            paths.append(a)
+
+    # default: show all
+    if not (show_l or show_w or show_c):
+        show_l = show_w = show_c = True
+
+    files = paths
+
+    total_l = 0
+    total_w = 0
+    total_c = 0
+
+    results = []
+    had_error = False
+
+    for file in files:
+        try:
+            l, w, c = count_file(file)
+        except FileNotFoundError:
+            print(
+                f"wc: {file}: No such file or directory",
+                file=sys.stderr,
+            )
+            had_error = True
+            continue
+
+        total_l += l
+        total_w += w
+        total_c += c
+
+        results.append((l,w,c, file))
+
+     # print per-file results (GNU-aligned formatting)
+    for l, w, c, file in results:
+
+        parts = []
+        if show_l:
+            parts.append(f"{l:3}")
+        if show_w:
+            parts.append(f"{w:4}")
+        if show_c:
+            parts.append(f"{c:4}")
+
+
+        print("".join(parts) + " " + file)
+
+    # print total if multiple files
+    if len(results) > 1:
+        parts = []
+
+        if show_l:
+            parts.append(f"{total_l:3}")
+        if show_w:
+            parts.append(f"{total_w:4}")
+        if show_c:
+            parts.append(f"{total_c:4}")
+
+
+        print("".join(parts) + " total")
+
+    if  had_error:
+        sys.exit(1)   
+
+
+if __name__ == "__main__":
+    main()