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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 to set LD_LIBRARY_PATH path in Environment Variable for using cppcms (chatgpt ans)

 ### Option 1: Setting the `LD_LIBRARY_PATH` Environment Variable


You can temporarily add the directory containing `libcppcms.so.2` to the `LD_LIBRARY_PATH` environment variable.


```sh

export LD_LIBRARY_PATH=/usr/local/lib:$LD_LIBRARY_PATH

./learnCppcms -c config.js

```


Replace `/usr/local/lib` with the actual path to the directory where `libcppcms.so.2` is installed.


### Option 2: Adding the Library Path to `/etc/ld.so.conf`


For a more permanent solution, you can add the library directory to the `/etc/ld.so.conf` file and run `ldconfig` to update the linker cache.


1. Open `/etc/ld.so.conf` in a text editor with root permissions:


    ```sh

    sudo nano /etc/ld.so.conf

    ```


2. Add the directory containing `libcppcms.so.2` (e.g., `/usr/local/lib`).


3. Save the file and exit the text editor.


4. Run `ldconfig` to update the linker cache:


    ```sh

    sudo ldconfig

    ```


### Option 3: Using a Wrapper Script


You can create a simple shell script to set the `LD_LIBRARY_PATH` environment variable before running your application:


1. Create a file named `run_learnCppcms.sh`:


    ```sh

    nano run_learnCppcms.sh

    ```


2. Add the following content to the file:


    ```sh

    #!/bin/bash

    export LD_LIBRARY_PATH=/usr/local/lib:$LD_LIBRARY_PATH

    ./learnCppcms -c config.js

    ```


    Replace `/usr/local/lib` with the actual path to the directory where `libcppcms.so.2` is installed.


3. Make the script executable:


    ```sh

    chmod +x run_learnCppcms.sh

    ```


4. Run your application using the script:


    ```sh

    ./run_learnCppcms.sh

    ```


### Additional Steps


1. **Ensure Libraries are Installed**: Verify that `libcppcms.so.2` is actually installed on your system. You can search for the file using:


    ```sh

    sudo find / -name libcppcms.so.2

    ```


2. **Check Symbolic Links**: Sometimes the issue is caused by missing symbolic links. Ensure that `libcppcms.so.2` is correctly linked in your library directory. For example, if the actual file is `libcppcms.so.2.0.0`, you might need to create a symlink:


    ```sh

    sudo ln -s /path/to/libcppcms.so.2.0.0 /usr/local/lib/libcppcms.so.2

    ``

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