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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...

Ubuntu Notes: Set up autossh as systemd useful-reminder commands

 sudo vim /etc/systemd/system/permanentAutossh.service ======================================== [Unit] Description=Keeps a tunnel to myOciFreeNat open After=network-online.target [Service] User=<username> Environment="AUTOSSH_GATETIME=0" ExecStart=/usr/bin/autossh -M 0 -q -N -o "ServerAliveInterval 60" -o "ServerAliveCountMax 3" -L 4322:127.0.0.1:5432 -i /<ssh_private_key_file_absolute_path> <username>@<ip_address> -p 22 [Install] WantedBy=multi-user.target ======================================== sudo systemctl daemon-reload sudo systemctl enable permanentAutossh sudo systemctl start permanentAutossh ================== sudo systemctl daemon-reload sudo systemctl restart permanentAutossh sudo systemctl status permanentAutossh ====================== sudo systemctl stop permanentAutossh sudo systemctl disable permanentAutossh sudo rm /etc/systemd/system/permanentAutossh.service

Reinstall Network-Manager in Ubuntu

 Assumptions: Network-Manager is somehow lost (or currepted) while updating/deleting some software and Internet access is lost. Internet access was there using data-cable usb port using mobile-internet connection. Get Logical Name of the port: Type in terminal  <sudo lshw -C network> you will get list of ports with there logical name Connect to internet using command: <sudo dhclient <your_port_name>> e.g. in my case it was <sudo dhclient usb0> Then reinstall Network-Manager using command: < sudo apt-get install network-manager> Done!

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!