cat done

Author: JanefrancessC

implement-shell-tools/.gitignore

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+node_modules/

implement-shell-tools/cat/customCat.js

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+#!/usr/bin/env node
+import { program } from "commander";
+import { promises as fs } from "node:fs";
+import process from "node:process";
+
+program
+  .name("customCat")
+  .description("CLI command to concatenate and print files")
+  .option("-n, --number", "Number all output lines starting, at 1")
+  .option("-b, --nonBlank", "Number only non-blank lines, starting at 1")
+  .argument("<files...>", "Files to read");
+
+program.parse();
+
+const argv = program.args;
+const options = program.opts();
+
+let lineNumber = 1;
+
+for (const filePath of argv) {
+  try {
+    const content = await fs.readFile(filePath, "utf-8");
+    const lines = content.split("\n");
+
+    if (lines[lines.length - 1] === "") lines.pop();
+
+    lines.forEach((line, index) => {
+      if (options.nonBlank) {
+        if (line.trim() !== "") {
+          process.stdout.write(`${(index + 1).toString().padStart(6)} ${line}\n`);
+          lineNumber++;
+        } else process.stdout.write(`${line}\n`);
+      } else if (options.number) {
+        process.stdout.write(`${(index + 1).toString().padStart(6)} ${line}\n`);
+      } else {
+        process.stdout.write(`${line}\n`);
+      }
+    });
+  } catch (error) {
+    console.error(`customCat: ${filePath}: No such file or directory.`);
+  }
+}

implement-shell-tools/package.json

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+{
+  "type": "module"
+}