feat: implement cat cmd with the -n and -b flags

Author: JanefrancessC

.gitignore

@@ -1 +1,3 @@
 node_modules
+demo*
+.*

implement-shell-tools/cat/cat.py

@@ -0,0 +1,38 @@
+#!/usr/bin/env python3
+
+import argparse
+import sys
+
+parser = argparse.ArgumentParser(
+    prog='cat',
+    description='CLI tool to concatenate and print files', 
+)
+
+parser.add_argument('-n', '--number', action='store_true', help='Number all outputs, starting at 1')
+parser.add_argument('-b', '--nonBlank', action='store_true', help='Number only non-blank lines, starting at 1')
+parser.add_argument('files', nargs='*', help='Files to read')
+
+args = parser.parse_args()
+# print(args.number, args.nonBlank, args.files)
+# print(sys.argv[0], sys.argv[1])
+
+
+for file in args.files:
+    count = 1
+    try:
+        with open(file, 'r') as f:
+            for line in f:
+                if args.nonBlank:
+                    if line.strip():
+                        print(f"{str(count).rjust(6)}\t{line}", end='')
+                        count += 1
+                    else:
+                        print(line, end="")
+                elif args.number:
+                    print(f"{str(count).rjust(6)}\t{line}", end='')
+                    count +=1
+                else:
+                    print(f"{line}", end="")
+   
+    except FileNotFoundError:
+        print(f"cat: {file}: No such file or directory.", file=sys.stderr)