added python the code for the cat command

Author: Luke-Manyamazi

implement-shell-tools/cat/cat.py

@@ -0,0 +1,38 @@
+import glob
+import argparse
+
+def cat(filepath, n=False, b=False, line_counter=None):
+    try:
+        with open(filepath) as f:
+            for line in f:
+                if b:
+                    if line.strip():
+                        print(f"{line_counter[0]:6}\t{line}", end='')
+                        line_counter[0] += 1
+                    else:
+                        print(line, end='')
+                elif n:
+                    print(f"{line_counter[0]:6}\t{line}", end='')
+                    line_counter[0] += 1
+                else:
+                    print(line, end='')
+    except FileNotFoundError:
+        print(f"cat: {filepath}: No such file or directory")
+
+def main():
+    parser = argparse.ArgumentParser(description = "Concatenate files and print on the standard output.")
+    parser.add_argument('-n', action='store_true', help='number all output lines')
+    parser.add_argument('-b', action='store_true', help='number non-empty output lines')
+    parser.add_argument('files', nargs='+', help='files to concatenate')
+    args = parser.parse_args()
+
+    files = []
+    for pattern in args.files:
+        files.extend(glob.glob(pattern) or [pattern])
+
+    line_counter = [1]
+    for file in sorted(files):
+        cat(file, args.n, args.b, line_counter)
+
+if __name__ == "__main__":
+    main()