Mirror of 437

implement-shell-tools/cat/cat.js

@@ -0,0 +1,40 @@
+import process from "node:process";
+import { promises as fs } from "node:fs";
+
+// THis will give an array without the path to node and to the file.
+const argv = process.argv.slice(2);
+
+//Get line numbers.
+const showNumbers = argv.includes("-n");
+const showNonBlankNumbers = argv.includes("-b");
+
+//filter the - from the array argv as it's a flag.
+const filePaths = argv.filter((arg) => !arg.startsWith("-"));
+let counterLines = 1;
+
+for (const path of filePaths) {
+  try {
+    const content = await fs.readFile(path, "utf-8");
+
+    //split the text at the new line character.
+    const splitLines = content.split("\n");
+
+    splitLines.forEach((line) => {
+      if (showNumbers) {
+        console.log(`${counterLines++}  ${line}`);
+      } else if (showNonBlankNumbers) {
+        // increment and show numbers only if the line is not empty.
+        if (line.trim() !== "") {
+          console.log(`${counterLines++}  ${line}`);
+        } else {
+          // print empty lines
+          console.log(line);
+        }
+      } else {
+        console.log(line);
+      }
+    });
+  } catch (error) {
+    console.log(`Could not read: ${path}`);
+  }
+}

implement-shell-tools/ls/ls.js

@@ -0,0 +1,28 @@
+import fs from "node:fs";
+import process from "node:process";
+
+// This will give an array without the path to node and to the file.
+const argv = process.argv.slice(2);
+
+// filter the flag to find the target folder.
+const filePaths = argv.filter((arg) => !arg.startsWith("-"));
+const showHiddenFiles = argv.includes("-a");
+
+// if no folder provide we use the current one
+const target = filePaths[0] || ".";
+// read the file.
+const files = fs.readdirSync(target);
+
+// save the result into the variable.
+let filteredFIles = files;
+if (!showHiddenFiles) {
+  filteredFIles = files.filter((file) => !file.startsWith("."));
+} else {
+  // we use spread operator to merge the paths.
+  filteredFIles = [".", "..", ...files];
+}
+
+// Print using -1 .
+filteredFIles.forEach((file) => {
+  console.log(file);
+});

implement-shell-tools/wc/wc.js

@@ -0,0 +1,40 @@
+import process, { exit } from "node:process";
+import fs from "node:fs";
+
+const argv = process.argv.slice(2);
+
+const showWords = argv.includes("-w");
+const showLines = argv.includes("-l");
+const showBytes = argv.includes("-c");
+const showCharacters = argv.includes("-m");
+
+//  filter flags, and getting the string of filename
+const filePaths = argv.filter((arg) => !arg.startsWith("-"));
+
+const noFlags = !showLines && !showCharacters && !showWords && !showCharacters;
+if (!filePaths) {
+  console.error("PLease provide a file path");
+  process.exit(1);
+}
+// loop trough the array to get each file path.
+filePaths.forEach((filePath) => {
+  const content = fs.readFileSync(filePath, "utf-8");
+
+  const lines = content.split("\n").length - 1;
+  const words = content
+    .trim()
+    .split(/\s+/)
+    .filter((word) => word != "").length;
+  // here I used Buffer.byteLength even if characters and bytes can be the same number .length, however sometimes an emoji or special characters can be heavier 2b or 4b
+  const bytes = Buffer.byteLength(content);
+  const characters = content.length;
+
+  let output = "";
+
+  if (showLines || noFlags) output += `${lines} `;
+  if (showWords || noFlags) output += `${words} `;
+  if (showBytes || noFlags) output += `${bytes} `;
+  if (showCharacters || noFlags) output += `${characters} `;
+
+  console.log(`${output} ${filePath}`);
+});

individual-shell-tools/sed/script-01.sh

@@ -4,4 +4,4 @@ set -euo pipefail
 
 # TODO: Write a command to output input.txt with all occurrences of the letter `i` replaced with `I`.
 # The output should contain 11 lines.
-# The first line of the output should be: "ThIs Is a sample fIle for experImentIng with sed.".
+# The first line of the output should be: "ThIs Is a sample fIle for experImentIng wIth sed.".