Adding implementation to count number of lines

Author: SaraTahir28

implement-shell-tools/cat/cat.js

@@ -0,0 +1,38 @@
+import { program } from "commander";
+import {promises as fs} from "node:fs"
+
+
+
+ //configuring the program here to run flags.
+
+program
+  .name("cat")
+  .description("Concatenate and print files")
+  .option("-n, --number", "Number all output lines")
+  .option("-b, --number-nonblank", "Number non-blank output lines") 
+  .argument("<files...>", "File paths to display")
+  .parse(process.argv);//Parse command line arguments (reads process.argv and interprets it)
+  
+const options = program.opts(); 
+const files = program.args; // Array of file paths passed as arguments
+
+let lineNumber = 1; // shared across all files, like GNU cat -n)
+
+for (const file of files) {
+  const content = await fs.readFile(file, "utf-8"); 
+  const lines = content.split("\n");
+
+  for (const line of lines) {
+   
+    if (options.number) {
+      console.log(`${lineNumber.toString().padStart(6)}  ${line}`); // adding padding for formatting 
+      lineNumber++;
+    }  
+    else{
+      console.log(line);  
+    } 
+    }
+  }
+
+
+