diff --git a/app/data/zadanie01/sum.txt b/app/data/zadanie01/sum.txt
index e69de29..615088b 100644
--- a/app/data/zadanie01/sum.txt
+++ b/app/data/zadanie01/sum.txt
@@ -0,0 +1 @@
+108
\ No newline at end of file
diff --git a/app/data/zadanieDnia/test.txt b/app/data/zadanieDnia/test.txt
index 47c17e3..c762954 100644
--- a/app/data/zadanieDnia/test.txt
+++ b/app/data/zadanieDnia/test.txt
@@ -1,7 +1,7 @@
-You Don't Know JS: ES6 & Beyond
-Foreword
+YoU DoN'T KnOw jS: eS6 & bEyOnD
+FoReWoRd
 
-Kyle Simpson is a thorough pragmatist.
+KyLe sImPsOn iS A ThOrOuGh pRaGmAtIsT.
 
-I can't think of higher praise than this. To me, these are two of the most important qualities that a software developer must have. That's right: must, not should. Kyle's keen ability to tease apart layers of the JavaScript programming language and present them in understandable and meaningful portions is second to none.
-[https://github.com/getify/You-Dont-Know-JS/blob/master/es6%20%26%20beyond/foreword.md]
\ No newline at end of file
+I CaN'T ThInK Of hIgHeR PrAiSe tHaN ThIs. To mE, tHeSe aRe tWo oF ThE MoSt iMpOrTaNt qUaLiTiEs tHaT A SoFtWaRe dEvElOpEr mUsT HaVe. ThAt's rIgHt: MuSt, NoTsHoUlD. kYlE'S KeEn aBiLiTy tO TeAsE ApArT LaYeRs oF ThE JaVaScRiPt pRoGrAmMiNg lAnGuAgE AnD PrEsEnT ThEm iN UnDeRsTaNdAbLe aNd mEaNiNgFuL PoRtIoNs iS SeCoNd tO NoNe.
+[hTtPs://gItHuB.CoM/GeTiFy/yOu-dOnT-KnOw-jS/BlOb/mAsTeR/Es6%20%26%20BeYoNd/fOrEwOrD.Md]
\ No newline at end of file
diff --git a/app/zadanie01.js b/app/zadanie01.js
index 8c20173..ea5b22f 100644
--- a/app/zadanie01.js
+++ b/app/zadanie01.js
@@ -1 +1,20 @@
-//Twój kod
\ No newline at end of file
+//Twój kod
+
+const fs = require('fs');
+
+fs.readFile('./data/zadanie01/input.json', 'utf8', (err, data) => {
+    if (err === null){
+        const arrParsed = JSON.parse(data);
+        const sum = arrParsed.reduce( (prev, curr) => { return prev + curr } );
+
+        fs.writeFile('./data/zadanie01/sum.txt', sum, err => {
+            if (err === null){
+                console.log('Poprawnie odczytano i zapisano plik! Suma wynosi: ', sum);
+            } else {
+                console.log('Błąd podczas zapisu pliku!', err);
+            }
+        });
+    } else {
+        console.log('Błąd podczas odczytu pliku!', err);
+    }
+});
\ No newline at end of file
diff --git a/app/zadanie02.js b/app/zadanie02.js
index 8c20173..b96a273 100644
--- a/app/zadanie02.js
+++ b/app/zadanie02.js
@@ -1 +1,19 @@
-//Twój kod
\ No newline at end of file
+//Twój kod
+
+const fs = require('fs');
+
+fs.readdir('./data/zadanie02', (err, files) => {
+    if (err === null){
+        files.forEach( file => {
+            fs.readFile(`./data/zadanie02/${file}`, 'utf8', (err, data) => {
+                if (err === null){
+                    console.log(`Poprawnie odczytano plik ${file}. Jego zawartość to: `, data);
+                } else {
+                    console.log('Błąd podczas odczytu pliku!', err);
+                }
+            });
+        });
+    } else {
+        console.log('Błąd podczas listowania katalogu!', err);
+    }
+});
\ No newline at end of file
diff --git a/app/zadanieDnia.js b/app/zadanieDnia.js
index 8c20173..a329f36 100644
--- a/app/zadanieDnia.js
+++ b/app/zadanieDnia.js
@@ -1 +1,24 @@
-//Twój kod
\ No newline at end of file
+//Twój kod
+
+const fs = require('fs');
+
+const textFile = process.argv[2];
+
+fs.readFile(textFile, 'utf8', (err, data) => {
+    if (err === null){
+        let trawkaText = "";
+        data.split("").map( (elem, index) => {
+            trawkaText += (index % 2 === 0) ? elem.toUpperCase() : elem.toLowerCase();
+        });
+
+        fs.writeFile(textFile, trawkaText, err => {
+            if (err === null){
+                console.log('Poprawnie odczytano i zapisano plik');
+            } else {
+                console.log('Błąd podczas zapisu pliku!', err);
+            }
+        });
+    } else {
+        console.log('Błąd podczas odczytu pliku!', err);
+    }
+});