London |26-JUL-SDC |Shaghayeghfar| Sprint 3 |Implement Shell Tools

implement-shell-tools/cat/cat.js

@@ -0,0 +1,55 @@
+const fs = require("fs");
+
+const args = process.argv.slice(2);
+
+let numberAllLines = false;
+let numberNonBlankLines = false;
+let startIndex = 0;
+let lineNumber = 1;
+
+// Check for flags
+for (let i = 0; i < args.length; i++) {
+  if (args[i] === "-n") {
+    numberAllLines = true;
+    startIndex++;
+  } else if (args[i] === "-b") {
+    numberNonBlankLines = true;
+    startIndex++;
+  } else {
+    break;
+  }
+}
+
+// Read each file
+for (let i = startIndex; i < args.length; i++) {
+  let fileName = args[i];
+
+  try {
+    let content = fs.readFileSync(fileName, "utf8");
+
+    // Remove the extra empty line if the file ends with "\n"
+    let lines = content.endsWith("\n")
+      ? content.slice(0, -1).split("\n")
+      : content.split("\n");
+
+    for (let j = 0; j < lines.length; j++) {
+      let line = lines[j];
+
+      if (numberAllLines) {
+        console.log(lineNumber + " " + line);
+        lineNumber++;
+      } else if (numberNonBlankLines) {
+        if (line.trim() === "") {
+          console.log(line);
+        } else {
+          console.log(lineNumber + " " + line);
+          lineNumber++;
+        }
+      } else {
+        console.log(line);
+      }
+    }
+  } catch (error) {
+    console.log("Cannot read file: " + fileName);
+  }
+}

implement-shell-tools/ls/ls.js

@@ -0,0 +1,61 @@
+const fs = require("fs");
+
+const args = process.argv.slice(2);
+
+let onePerLine = false;
+let showHidden = false;
+let paths = [];
+
+// Check for flags
+for (let i = 0; i < args.length; i++) {
+  if (args[i] === "-1") {
+    onePerLine = true;
+  } else if (args[i] === "-a") {
+    showHidden = true;
+  } else {
+    paths.push(args[i]);
+  }
+}
+
+// Use current directory if no path is given
+if (paths.length === 0) {
+  paths.push(".");
+}
+
+for (let i = 0; i < paths.length; i++) {
+  let path = paths[i];
+
+  try {
+    // Check if the path is a file
+    if (fs.statSync(path).isFile()) {
+      console.log(path);
+    } else {
+      let files = fs.readdirSync(path);
+
+      // Sort files like ls command
+      files.sort();
+
+      // Print each file
+      for (let j = 0; j < files.length; j++) {
+        let file = files[j];
+
+        // Skip hidden files unless -a is used
+        if (!showHidden && file.startsWith(".")) {
+          continue;
+        }
+
+        if (onePerLine) {
+          console.log(file);
+        } else {
+          process.stdout.write(file + " ");
+        }
+      }
+
+      if (!onePerLine) {
+        console.log();
+      }
+    }
+  } catch (error) {
+    console.log("Cannot access: " + path);
+  }
+}

implement-shell-tools/wc/wc.js

@@ -0,0 +1,103 @@
+const fs = require("fs");
+
+// Get arguments after "node wc.js"
+const args = process.argv.slice(2);
+
+let countLines = false;
+let countWords = false;
+let countBytes = false;
+
+let files = [];
+
+// Read arguments
+for (let arg of args) {
+  if (arg === "-l") {
+    countLines = true;
+  } else if (arg === "-w") {
+    countWords = true;
+  } else if (arg === "-c") {
+    countBytes = true;
+  } else {
+    files.push(arg);
+  }
+}
+
+// If no flags are given, wc shows all three
+if (!countLines && !countWords && !countBytes) {
+  countLines = true;
+  countWords = true;
+  countBytes = true;
+}
+
+// Totals
+let totalLines = 0;
+let totalWords = 0;
+let totalBytes = 0;
+let filesCounted = 0;
+
+// Function to count one file
+function countFile(fileName) {
+  try {
+    const content = fs.readFileSync(fileName, "utf8");
+
+    let lines = content.split("\n").length - 1;
+
+    let words = content
+      .trim()
+      .split(/\s+/)
+      .filter((word) => word.length > 0).length;
+
+    let bytes = Buffer.byteLength(content);
+
+    totalLines += lines;
+    totalWords += words;
+    totalBytes += bytes;
+    filesCounted++;
+
+    let result = "";
+
+    if (countLines) {
+      result += lines + " ";
+    }
+
+    if (countWords) {
+      result += words + " ";
+    }
+
+    if (countBytes) {
+      result += bytes + " ";
+    }
+
+    result += fileName;
+
+    console.log(result);
+  } catch (error) {
+    console.log("Cannot read file: " + fileName);
+  }
+}
+
+// Run wc for every file
+for (let file of files) {
+  countFile(file);
+}
+
+// Print totals if more than one file was counted
+if (filesCounted > 1) {
+  let result = "";
+
+  if (countLines) {
+    result += totalLines + " ";
+  }
+
+  if (countWords) {
+    result += totalWords + " ";
+  }
+
+  if (countBytes) {
+    result += totalBytes + " ";
+  }
+
+  result += "total";
+
+  console.log(result);
+}