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How to use gdb in Ubuntu Terminal

Here's a practical, minimal guide for using GDB in Ubuntu terminal — from launching to setting breakpoints and navigating your code. 🧰 Step 1: Compile with Debug Symbols Use -g and disable optimizations ( -O0 preferred for debugging): bash Copy Edit g++ -g -O0 -o myprog myprog.cpp 🚀 Step 2: Launch GDB bash Copy Edit gdb ./myprog You'll see a (gdb) prompt. 🎯 Step 3: Set Breakpoints You can set breakpoints in three main ways : ✅ a. At a function gdb Copy Edit (gdb) break main ✅ b. At a specific file and line gdb Copy Edit (gdb) break myprog.cpp:42 ✅ c. At a method in a class gdb Copy Edit (gdb) break MyClass::doSomething If the symbol is mangled (C++), GDB usually demangles automatically, especially if compiled with -g . ▶️ Step 4: Run the Program gdb Copy Edit (gdb) run 🧭 Step 5: Navigate Command Meaning next or n Step over current line step or s Step into function call finish Run until current function returns continue or c Continue until...
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How do I increased Swap Memory of Ubuntu OS using terminal from 1GB to 7GB

 Hi, I have increase my Ubuntu OS swap memory from 1GB to 7GB by adding additional 6GB space to swap. Process which I followed is as follows: 1> Check previous Swap Memory: cat /proc/swaps 2> Check previous Swap Memory: swapon 3> Check previous Swap Memory: free 4> Create new Swap Memory: sudo dd if=/dev/zero of=/newswap bs=1024 count=6M 5> Set permissions for new Swap Memory sudo chmod 0600 /newswap 6> Bake new swap: sudo mkswap /newswap 7> Turn on new swap: sudo swapon /newswap 8> Check new Swap Memory: swapon 9> Modify /etc/fstab file by adding following lines at the end /newswap    swap    swap   defaults 0 0 Done!
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Google Cloud Plateform VM Instances: How to connect one VM Instance to other using SSH and Internal IP Address

 Dear Friends, all of us know that there are two kinds of IP Address that can be assigned to GCP VM Instances (i.e Compute Engine), now if you take external IP address, without any reason then you will have to pay since external IP address is not free. So if you need to connect two compute engines via internal IP address using terminal for same region, via SSH, process is same as you connect via extermal IP address. i.e ssh <username>@<internal_ip_address>. Other advantage of connection via internal IP address is that it uses Internal LAN instead of Internet Data for communication will in turn will save lot of energy.
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Update Time-Zone in Ubuntu 20.04 terminal

Check time zone by date command  sudo timedatectl set-timezone <your_timezone> eg sudo timedatectl set-timezone Asia/Kolkata Then after setting check again using date command. Note: After updating timezone always restart using command sudo reboot, for proper functioning of cronzobs, etc
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Set Up Default Password for Postgres User

 Upon installing postgres, there is no password for Postgres User This is the way to set up default password for Postgres User in Linux Open terminal Type: sudo -u postgres psql <-p portNo> eg sudo -u postgres psql -p 5433 or sudo -u postgres psql for default port 5432 Type: postgres=# ALTER USER postgres PASSWORD '<your desired password>'; Type: \q to exit postgres and return back to terminal login DONE!
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How to do Instance Scheduling in Google Cloud Plateform

Instance Scheduling provides easy way to turn copmpute engine instance on & off at particular timing very easily. This the the way, how I achieved this for doing this work. Log in to console.cloude.google.com Go to IAM & Admin -> Roles Choose Create roles and create role with permissions:  Go to IAM & Admin -> IAM Click Google -Provided Role grant... Search for service-<Your-ProjectId>@compute-system.iam.gserviceaccount.com in filter and edit to add role you created in Step 2 above Go to Compute Engine -> VM Instances -> Instance Schedule Create an instance schedule with start - stop timing as per your requirement you can choose start-stop timing as per CRON format of Linux for further detailing. Now once instance schedule is created, click it and click Add Instance to Schedule Choose your VM Instances for this schedule and its done Hope you enjoyed this reading and this reading may help you for future project.
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Java Encryption - Decryption Code

package myLib; import java.io.UnsupportedEncodingException; import java.security.GeneralSecurityException; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.security.SecureRandom; import javax.crypto.Cipher; import javax.crypto.NoSuchPaddingException; import javax.crypto.spec.IvParameterSpec; import javax.crypto.spec.SecretKeySpec; import javax.xml.bind.DatatypeConverter; import org.apache.xml.security.exceptions.Base64DecodingException; /**  *  * @author Mohit Kumar Gupta  */ public class CryptoAES256 {    public static void main(String[] args) {         try {             String passP = "Bar12345Barjhggfh12345"; // 128 bit key             String encryptedString = encrypt(passP, "Hello Mohit");             System.out.println("EncryptedString= " + encryptedString);             Stri...
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