London | 26-March-SDC | Ammad Ur Rehman | Sprint 3 | Implement Shell Tools

implement-shell-tools/cat/cat.mjs

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+import { program } from "commander";
+import { promises as fs } from "node:fs";
+
+program.name("cat");
+program.description("simple cat clone");
+program.option("-n, --number", "number all output lines");
+program.option("-b, --number-nonblank", "number non-empty output lines");
+program.argument("[paths...]", "file(s) to process");
+program.parse();
+
+const { number, numberNonblank } = program.opts();
+const paths = program.args;
+
+async function processFile(path) {
+  try {
+    const stat = await fs.stat(path);
+
+    if (stat.isDirectory()) {
+      console.error(`${path}: Is a directory`);
+      return;
+    }
+
+    const content = await fs.readFile(path, { encoding: "utf-8" });
+    const lines = content.split("\n");
+    const hasTrailingNewLine = content.endsWith("\n");
+    const effectiveLines = hasTrailingNewLine ? lines.slice(0, -1) : lines;
+    let lineNumber = 1;
+
+    const processed = effectiveLines.map((line) => {
+      if (numberNonblank) {
+        if (line.trim() !== "") {
+          const result = `${lineNumber}\t${line}`;
+          lineNumber += 1;
+          return result;
+        }
+
+        return line;
+      }
+
+      if (number) {
+        const result = `${lineNumber}\t${line}`;
+        lineNumber += 1;
+        return result;
+      }
+
+      return line;
+    });
+
+    const output = processed.join("\n");
+    console.log(output);
+  } catch (error) {
+    console.error(`${path}: ${error.message}`);
+  }
+}
+
+try {
+  for (const path of paths) {
+    await processFile(path);
+  }
+} catch (error) {
+  console.error(error.message);
+}

implement-shell-tools/cat/package.json

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+{
+  "name": "cat",
+  "version": "1.0.0",
+  "type": "module",
+  "description": "You should already be familiar with the `cat` command line tool.",
+  "main": "index.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "commander": "^14.0.3"
+  }
+}

implement-shell-tools/ls/ls.mjs

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+import { program } from "commander";
+import { promises as fs } from "node:fs";
+import process from "node:process";
+
+program.name("ls");
+program.description("simple ls clone");
+program.option("-1", "list one file per line");
+program.option("-a", "show hidden files");
+program.argument("<path>");
+program.parse();
+
+const argv = program.args;
+
+if (argv.length != 1) {
+  console.error(`Expected exactly 1 argument (a path) to be passed but got ${argv.length}`);
+  process.exit(1);
+}
+
+const options = program.opts();
+const path = argv[0];
+
+try {
+  const stat = await fs.stat(path);
+
+  if (stat.isDirectory()) {
+    let files = await fs.readdir(path);
+
+    if (!options.a) {
+      files = files.filter((file) => !file.startsWith("."));
+    }
+
+    if (options["1"]) {
+      for (const file of files) {
+        console.log(file);
+      }
+    } else {
+      const output = files.join("\t");
+      console.log(output);
+    }
+  } else {
+    console.log(path);
+  }
+} catch (err) {
+  console.log(err.message);
+}

implement-shell-tools/ls/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "commander",
+  "version": "1.0.0",
+  "type": "module",
+  "description": "You should already be familiar with the `ls` command line tool.",
+  "main": "index.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "commander": "^14.0.3"
+  }
+}

implement-shell-tools/wc/package.json

@@ -0,0 +1,16 @@
+{
+  "name": "wc",
+  "version": "1.0.0",
+  "type": "module",
+  "description": "You should already be familiar with the `wc` command line tool.",
+  "main": "index.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "commander": "^14.0.3"
+  }
+}

implement-shell-tools/wc/wc.mjs

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+import { program } from "commander";
+import { promises as fs } from "node:fs";
+
+program.name("wc");
+program.description("simple wc clone");
+program.option("-w, --words", "print word count");
+program.option("-l, --lines", "print line count");
+program.option("-c, --bytes", "print byte count");
+program.argument("[paths...]", "file(s) to process");
+program.parse();
+
+const options = program.opts();
+const paths = program.args;
+
+const noFlags = !options.words && !options.lines && !options.bytes;
+const showWords = options.words || noFlags;
+const showLines = options.lines || noFlags;
+const showBytes = options.bytes || noFlags;
+
+function count(content) {
+  const lines = content.split("\n").length - 1;
+  const words = content.trim().split(/\s+/).filter(Boolean).length;
+  const bytes = Buffer.byteLength(content);
+
+  return { lines, words, bytes };
+}
+
+function formatCounts({ lines, words, bytes }, label = "") {
+  const output = [];
+
+  if (showLines) {
+    output.push(lines.toString().padStart(8));
+  }
+
+  if (showWords) {
+    output.push(words.toString().padStart(8));
+  }
+
+  if (showBytes) {
+    output.push(bytes.toString().padStart(8));
+  }
+
+  if (label) {
+    output.push(label);
+  }
+
+  return output.join(" ");
+}
+
+async function processFile(path) {
+  try {
+    const stat = await fs.stat(path);
+
+    if (stat.isDirectory()) {
+      console.error(`${path}: Is a directory`);
+      return;
+    }
+
+    const content = await fs.readFile(path, { encoding: "utf-8" });
+    const counts = count(content);
+    const output = formatCounts(counts, path);
+
+    console.log(output);
+  } catch (err) {
+    console.error(`${path}: ${err.message}`);
+  }
+}
+
+try {
+  for (const path of paths) {
+    await processFile(path);
+  }
+} catch (err) {
+  console.error(err.message);
+}