Birmingham | 2026-MAR-SDC | Joy Opachavalit | Sprint 3 | Implement shell tools

implement-shell-tools/cat/cat.js

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+#!/usr/bin/env node
+
+const fs = require('fs');
+const path = require('path');
+
+function cat(files, options) {
+  let lineNumber = 1;
+
+  files.forEach((file) => {
+    const filePath = path.resolve(file);
+
+    try {
+      const data = fs.readFileSync(filePath, 'utf8');
+      const lines = data.split('\n');
+
+      lines.forEach((line) => {
+        if (options.numberNonEmpty && line.trim()) {
+          console.log(`${lineNumber}\t${line}`);
+          lineNumber++;
+        } else if (options.numberLines) {
+          console.log(`${lineNumber}\t${line}`);
+          lineNumber++;
+        } else {
+          console.log(line);
+        }
+      });
+    } catch (err) {
+      console.error(`cat: ${file}: No such file or directory`);
+    }
+  });
+}
+
+function main() {
+  const args = process.argv.slice(2);
+  const options = {
+    numberLines: false,
+    numberNonEmpty: false,
+  };
+
+  const files = [];
+
+  args.forEach((arg) => {
+    if (arg === '-n') {
+      options.numberLines = true;
+    } else if (arg === '-b') {
+      options.numberNonEmpty = true;
+    } else {
+      files.push(arg);
+    }
+  });
+
+  if (files.length === 0) {
+    console.error('Usage: node cat.js [-n | -b] <file>...');
+    process.exit(1);
+  }
+
+  cat(files, options);
+}
+
+main();

implement-shell-tools/ls/ls.js

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+#!/usr/bin/env node
+
+const fs = require('fs');
+const path = require('path');
+
+function listFiles(directory, options) {
+  try {
+    const files = fs.readdirSync(directory, { withFileTypes: true });
+
+    files.forEach((file) => {
+      if (!options.all && file.name.startsWith('.')) {
+        return; // Skip hidden files unless -a is specified
+      }
+      console.log(file.name);
+    });
+  } catch (err) {
+    console.error(`ls: cannot access '${directory}': No such file or directory`);
+  }
+}
+
+function main() {
+  const args = process.argv.slice(2);
+  const options = {
+    all: false,
+  };
+
+  let directories = ['.'];
+
+  args.forEach((arg) => {
+    if (arg === '-1') {
+      // -1 is the default behavior, so no action needed
+    } else if (arg === '-a') {
+      options.all = true;
+    } else {
+      directories = [arg];
+    }
+  });
+
+  directories.forEach((directory) => {
+    listFiles(directory, options);
+  });
+}
+
+main();

implement-shell-tools/wc/wc.js

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+#!/usr/bin/env node
+
+const fs = require('fs');
+const path = require('path');
+
+function countFile(filePath, options) {
+  try {
+    const data = fs.readFileSync(filePath, 'utf8');
+
+    const lines = data.split('\n').length;
+    const words = data.split(/\s+/).filter(Boolean).length;
+    const bytes = Buffer.byteLength(data, 'utf8');
+
+    if (options.lines) {
+      console.log(`${lines}\t${filePath}`);
+    } else if (options.words) {
+      console.log(`${words}\t${filePath}`);
+    } else if (options.bytes) {
+      console.log(`${bytes}\t${filePath}`);
+    } else {
+      console.log(`${lines}\t${words}\t${bytes}\t${filePath}`);
+    }
+  } catch (err) {
+    console.error(`wc: ${filePath}: No such file or directory`);
+  }
+}
+
+function main() {
+  const args = process.argv.slice(2);
+  const options = {
+    lines: false,
+    words: false,
+    bytes: false,
+  };
+
+  const files = [];
+
+  args.forEach((arg) => {
+    if (arg === '-l') {
+      options.lines = true;
+    } else if (arg === '-w') {
+      options.words = true;
+    } else if (arg === '-c') {
+      options.bytes = true;
+    } else {
+      files.push(arg);
+    }
+  });
+
+  if (files.length === 0) {
+    console.error('Usage: wc [-l | -w | -c] <file>...');
+    process.exit(1);
+  }
+
+  files.forEach((file) => {
+    const filePath = path.resolve(file);
+    countFile(filePath, options);
+  });
+}
+
+main();