London | 26-SDC-Mar | Ebrahim Beiati-Asl | Sprint 3 | implements-shell-tool

implement-shell-tools/cat/cat.js

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+#!/usr/bin/env node
+const fs = require("node:fs");
+//shared line counter across all files(matches cat -n)
+let globalLineCounter = 1;
+
+function printFile(filePath, options) {
+  try {
+    const content = fs.readFileSync(filePath, "utf-8");
+    const lines = content.split("\n");
+
+    lines.forEach((line) => {
+      let prefix = "";
+
+      const shouldNumber = 
+        options.numberMode === "all" ||
+        (options.numberMode === "non-empty" && line.trim() !== "");
+
+        if (shouldNumber) {
+          prefix = `${String(globalLineCounter).padStart(6)}\t`;
+          globalLineCounter++;
+        }
+
+      process.stdout.write(`${prefix}${line}\n`);
+    });
+  } catch (error) {
+    console.error(`cat: ${filePath}: ${error.message}`);
+  }
+}
+
+function main() {
+  const args = process.argv.slice(2);
+
+  const options = {
+    numberMode: "off",
+  };
+
+  const files = [];
+  args.forEach((arg) => {
+    if (arg === "-n") {
+      options.numberMode = "all";
+    } else if (arg === "-b") {
+      options.numberMode = "non-empty";
+    } else {
+      files.push(arg);
+    }
+  });
+
+  if (files.length === 0) {
+    console.log("cat: missing file operand");
+    process.exit(1);
+  }
+
+  files.forEach((file) => {
+    printFile(file, options);
+  });
+}
+
+main();

implement-shell-tools/ls/ls.js

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+#!/usr/bin/env node
+const fs = require("node:fs");
+function listDirectory(dirPath, showAll, onePerLine) {
+  try {
+    const entries = fs.readdirSync(dirPath, { withFileTypes: true });
+    const filtered = entries.filter(
+      (entry) => showAll || !entry.name.startsWith("."),
+    );
+
+    if (onePerLine) {
+      filtered.forEach((entry) => console.log(entry.name));
+    } else {
+      const names = filtered.map((entry) => entry.name);
+      console.log(names.join("  "));
+    }
+  } catch (error) {
+    console.error(`Error reading directory ${dirPath}: ${error.message}`);
+    process.exitCode = 1;
+  }
+}
+function main() {
+  const args = process.argv.slice(2);
+  // Check for options
+  const showAll = args.includes("-a");
+  const onePerLine = args.includes("-1");
+  //remove options from args
+  let directories = args.filter((arg) => arg !== "-a" && arg !== "-1");
+
+  // Default to current directory if no directories are specified
+  if (directories.length === 0) {
+    directories = [process.cwd()];
+  }
+  directories.forEach((arg, index) => {
+    try {
+      const stats = fs.statSync(arg);
+
+      if (stats.isDirectory()) {
+        //Print header if multiple directories are listed
+        if (directories.length > 1) {
+          console.log(`${arg}:`)
+        };
+        listDirectory(arg, showAll, onePerLine);
+        //add a blank line between directory listings if there are multiple directories
+        if (directories.length > 1 && index < directories.length - 1){
+          console.log(""); 
+        }
+
+      } else {
+        console.log(arg); // single file
+      }
+    } catch (error) {
+      console.error(`Error accessing ${arg}: ${error.message}`);
+      process.exitCode = 1;
+    }
+  });
+}
+main();

implement-shell-tools/wc/wc.js

@@ -0,0 +1,74 @@
+#!/usr/bin/env node
+const fs = require("node:fs");
+// Function to count lines, words, and bytes in a file
+function countFileContent(content) {
+  const lines = content.split("\n").length; // Count lines by splitting on newline characters
+  const words = content.trim().split(/\s+/).filter(Boolean).length; // Split by whitespace and filter out empty strings
+  const bytes = Buffer.byteLength(content, "utf8");
+  return { lines, words, bytes };
+}
+
+//print counts in the format of wc according to options
+function printCounts(filePath, counts, options) {
+  const parts = [];
+  if (options.line) parts.push(counts.lines);
+  if (options.word) parts.push(counts.words);
+  if (options.byte) parts.push(counts.bytes);
+
+  console.log(parts.join("\t"), filePath);
+}
+
+function main() {
+  const args = process.argv.slice(2);
+  const options = {
+    line: false,
+    word: false,
+    byte: false,
+  };
+
+  //Separate options from file paths
+  const files = [];
+  args.forEach((arg) => {
+    if (arg === "-l") options.line = true;
+    else if (arg === "-w") options.word = true;
+    else if (arg === "-c") options.byte = true;
+    else files.push(arg);
+  });
+
+  if (files.length === 0) {
+    console.error("No files specified");
+    process.exit(1);
+  }
+  //If no specific count options are provided, default to all counts (lines, words, bytes)
+  if (!options.line && !options.word && !options.byte) {
+    options.line = true;
+    options.word = true;
+    options.byte = true;
+  }
+
+  let totalCounts = { lines: 0, words: 0, bytes: 0 };
+  const multipleFiles = files.length > 1;
+
+  files.forEach((file) => {
+    try {
+      const content = fs.readFileSync(file, "utf-8");
+      const counts = countFileContent(content);
+
+      // Sum counts for total if multiple files
+      totalCounts.lines += counts.lines;
+      totalCounts.words += counts.words;
+      totalCounts.bytes += counts.bytes;
+
+      printCounts(file, counts, options);
+    } catch (error) {
+      console.error(`Error reading file ${file}: ${error.message}`);
+      process.exitCode = 1;
+    }
+  });
+
+  // If multiple files, print total counts
+  if (multipleFiles) {
+    printCounts("total", totalCounts, options);
+  }
+}
+main();