Add python implementation of catCommand and .gitignore file

Author: ike-agu

implement-shell-tools/cat/README.md

@@ -1,4 +1,4 @@
-# Implement `cat`
+# Implement `cat` in python
 
 You should already be familiar with the `cat` command line tool.
 
@@ -15,3 +15,20 @@ It must act the same as `cat` would, if run from the directory containing this R
 Matching any additional behaviours or flags are optional stretch goals.
 
 We recommend you start off supporting no flags, then add support for `-n`, then add support for `-b`.
+
+*========commands for running the scripts========
+
+* No flags
+python cat.py sample-files/1.txt
+
+* Number every line (-n)
+python cat.py -n sample-files/1.txt
+
+* Display all files in directory(shell expands *.txt)
+python cat.py sample-files/*.txt
+
+* Number every line across multiple files(including empty ones)
+python cat.py -n sample-files/*.txt
+
+* Number non-empty lines only (-b)
+python cat.py -b sample-files/3.txt

implement-shell-tools/cat/cat.py

@@ -0,0 +1,50 @@
+import argparse
+# -------------------------------------------
+# Set up the argument parser
+# -------------------------------------------
+
+parser = argparse.ArgumentParser(
+    prog ="display-file-content",
+    description = "Implement cat command with -n and -b flag support",
+    )
+
+parser.add_argument("-n", "--number-all-lines",
+                    action="store_true",
+                    help="Number every line in the file"
+                    )
+
+parser.add_argument("-b", "--number-non-empty-lines",
+                    action="store_true",
+                    help="Number non empty lines in the file"
+                    )
+
+parser.add_argument("paths", nargs="+", help="File paths to process")
+
+args = parser.parse_args()
+
+# -------------------------------------------
+#  Implement functionality
+# -------------------------------------------
+
+line_number = 1
+
+for filepath in args.paths:
+    with open(filepath, "r", encoding="utf-8") as f:
+        content = f.read()
+
+        lines = content.split("\n")
+
+        for line in lines:
+            if args.number_all_lines:
+                print(f"{line_number} {line}")
+                line_number += 1
+
+            elif args.number_non_empty_lines:
+                if line.strip() == "":
+                    print(line)
+                else:
+                    print(f"{line_number} {line}")
+                    line_number +=1
+
+            else:
+                print(line)