From 276fc2be1d76d7ee93ca1a78f2f3d80722ee4542 Mon Sep 17 00:00:00 2001
From: Jamal Laqdiem <jlaqdiem@gmail.com>
Date: Sat, 21 Mar 2026 08:46:45 +0000
Subject: [PATCH 1/4] implementing a logic that behive as cat command

---
 implement-shell-tools/cat/cat.js | 40 ++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 implement-shell-tools/cat/cat.js

diff --git a/implement-shell-tools/cat/cat.js b/implement-shell-tools/cat/cat.js
new file mode 100644
index 000000000..7c88bd963
--- /dev/null
+++ b/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}`);
+  }
+}

From 8675a8b2fca34151e3d2c70721e021bdb15e9417 Mon Sep 17 00:00:00 2001
From: Jamal Laqdiem <jlaqdiem@gmail.com>
Date: Tue, 24 Mar 2026 14:24:42 +0000
Subject: [PATCH 2/4] Solving The exercise for ls command.

---
 implement-shell-tools/ls/ls.js | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 implement-shell-tools/ls/ls.js

diff --git a/implement-shell-tools/ls/ls.js b/implement-shell-tools/ls/ls.js
new file mode 100644
index 000000000..18b2116e0
--- /dev/null
+++ b/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);
+});

From 99cb233b094f5a4c53bbdeaec48c7964a09e2570 Mon Sep 17 00:00:00 2001
From: Jamal Laqdiem <jlaqdiem@gmail.com>
Date: Thu, 26 Mar 2026 11:00:56 +0000
Subject: [PATCH 3/4] feat: create a script that behave like wc command.

---
 implement-shell-tools/wc/wc.js | 40 ++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 implement-shell-tools/wc/wc.js

diff --git a/implement-shell-tools/wc/wc.js b/implement-shell-tools/wc/wc.js
new file mode 100644
index 000000000..2860444ae
--- /dev/null
+++ b/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}`);
+});

From e1d7c80532a5eec8dc7b17dfb87eb254678b0fd0 Mon Sep 17 00:00:00 2001
From: Jamal Laqdiem <jlaqdiem@gmail.com>
Date: Sat, 11 Apr 2026 09:30:48 +0100
Subject: [PATCH 4/4] FIx:  Implement the missing logics.

---
 implement-shell-tools/.gitignore |  1 +
 implement-shell-tools/cat/cat.js | 30 +++++++++++++++++++-----------
 implement-shell-tools/ls/ls.js   |  4 ++++
 implement-shell-tools/wc/wc.js   | 28 +++++++++++++++++-----------
 4 files changed, 41 insertions(+), 22 deletions(-)
 create mode 100644 implement-shell-tools/.gitignore

diff --git a/implement-shell-tools/.gitignore b/implement-shell-tools/.gitignore
new file mode 100644
index 000000000..1d17dae13
--- /dev/null
+++ b/implement-shell-tools/.gitignore
@@ -0,0 +1 @@
+.venv
diff --git a/implement-shell-tools/cat/cat.js b/implement-shell-tools/cat/cat.js
index 7c88bd963..4c9b552a7 100644
--- a/implement-shell-tools/cat/cat.js
+++ b/implement-shell-tools/cat/cat.js
@@ -10,6 +10,16 @@ const showNonBlankNumbers = argv.includes("-b");
 
 //filter the - from the array argv as it's a flag.
 const filePaths = argv.filter((arg) => !arg.startsWith("-"));
+
+const flagsUsed = argv.filter((arg) => arg.startsWith("-"));
+const supportedFlags = ["-n", "-b"];
+for (const flag of flagsUsed) {
+  if (!supportedFlags.includes(flag)) {
+    console.error(`Invalid option try 'node cat.js --help' for more info.`);
+    process.exit(1);
+  }
+}
+
 let counterLines = 1;
 
 for (const path of filePaths) {
@@ -20,21 +30,19 @@ for (const path of filePaths) {
     const splitLines = content.split("\n");
 
     splitLines.forEach((line) => {
-      if (showNumbers) {
-        console.log(`${counterLines++}  ${line}`);
-      } else if (showNonBlankNumbers) {
-        // increment and show numbers only if the line is not empty.
+      let prefix = "";
+
+      if (showNonBlankNumbers) {
         if (line.trim() !== "") {
-          console.log(`${counterLines++}  ${line}`);
-        } else {
-          // print empty lines
-          console.log(line);
+          prefix = `${counterLines++}  `;
         }
-      } else {
-        console.log(line);
+      } else if (showNumbers) {
+        prefix = `${counterLines++}  `;
       }
+      console.log(`${prefix}${line}`);
     });
   } catch (error) {
-    console.log(`Could not read: ${path}`);
+    console.error(`Could not read: ${path}`);
+    process.exit(1);
   }
 }
diff --git a/implement-shell-tools/ls/ls.js b/implement-shell-tools/ls/ls.js
index 18b2116e0..e1d3b4b75 100644
--- a/implement-shell-tools/ls/ls.js
+++ b/implement-shell-tools/ls/ls.js
@@ -8,6 +8,10 @@ const argv = process.argv.slice(2);
 const filePaths = argv.filter((arg) => !arg.startsWith("-"));
 const showHiddenFiles = argv.includes("-a");
 
+if (filePaths.length > 1) {
+  console.error("Error: This version only supports one directory path a time.");
+  process.exit(1);
+}
 // if no folder provide we use the current one
 const target = filePaths[0] || ".";
 // read the file.
diff --git a/implement-shell-tools/wc/wc.js b/implement-shell-tools/wc/wc.js
index 2860444ae..44e1a1429 100644
--- a/implement-shell-tools/wc/wc.js
+++ b/implement-shell-tools/wc/wc.js
@@ -3,16 +3,22 @@ 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");
+let showWords = argv.includes("-w");
+let showLines = argv.includes("-l");
+let showBytes = argv.includes("-c");
+let 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) {
+// if no flags enable all.
+if (!showLines && !showCharacters && !showWords && !showBytes) {
+  showLines = true;
+  showCharacters = true;
+  showWords = true;
+  showBytes = true;
+}
+// fix bug .length ===0 will be true if nothing provided, instead !filePath will return empty array which result true.
+if (filePaths.length === 0) {
   console.error("PLease provide a file path");
   process.exit(1);
 }
@@ -31,10 +37,10 @@ filePaths.forEach((filePath) => {
 
   let output = "";
 
-  if (showLines || noFlags) output += `${lines} `;
-  if (showWords || noFlags) output += `${words} `;
-  if (showBytes || noFlags) output += `${bytes} `;
-  if (showCharacters || noFlags) output += `${characters} `;
+  if (showLines) output += `${lines} `;
+  if (showWords) output += `${words} `;
+  if (showBytes) output += `${bytes} `;
+  if (showCharacters) output += `${characters} `;
 
   console.log(`${output} ${filePath}`);
 });