cat implementation

Author: Fatma Degirmenci

implement-shell-tools/cat/cat.js

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+import { program } from "commander";
+import { promises as fs } from "node:fs";
+
+program
+  .name("cat command")
+  .description("create cat command")
+  .option("-n", "Number all lines")
+  .option("-b", "Number non-empty lines")
+  .argument("<paths...>", "File paths");
+
+program.parse();
+const paths = program.args;
+const number = program.opts().n;
+const nonEmptyLine = program.opts().b;
+
+let lineNumber = 1;
+ 
+for (const path of paths) {
+  try {
+    const read = await fs.readFile(path, "utf-8");
+    const lines = read.split("\n");
+    for (let i of lines) {
+      if (number) {
+        console.log(`${String(lineNumber).padStart(6, " ")} ${i}`);
+        lineNumber++;
+      } else if (nonEmptyLine) {
+        if (i.trim() !== "") {
+          console.log(`${String(lineNumber).padStart(6, " ")} ${i}`);
+          lineNumber++;
+        } else {
+          console.log(i);
+        }
+      } else {
+        console.log(i);
+      }
+    }
+  } catch (err) {
+    console.error(`File could not read: ${path}`);
+  }
+}

implement-shell-tools/cat/package-lock.json

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+{
+  "name": "cat",
+  "version": "1.0.0",
+  "description": "You should already be familiar with the `cat` command line tool.",
+  "main": "cat.js",
+  "type": "module",
+  "dependencies": {
+    "commander": "^14.0.2",
+    "glob": "^13.0.0",
+    "lru-cache": "^11.2.2",
+    "minimatch": "^10.1.1",
+    "minipass": "^7.1.2",
+    "path-scurry": "^2.0.1"
+  },
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC"
+}