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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 Add Free SSL Certificate from LetsEncrypt via Certbot in your Java Tomcat / Tomee website?

Assumptions:
1. You are using Linux / Debian Server
2. You are using Compute Engine
3. You are using Google Domains
4. Set $JAVA_HOME=<path to your java base directory>
5. Set $CATALINA_BASE=<path to your Tomcat / Tomee base directory>

-------------------------------------------------------------------------------------

Procedure:
2. In selection option, 
    a) My website running on <none of the above>
    b) Operating system using <as per your operating system>, <Debian 10 in my case>
3. Type command sudo apt-get install certbot
4. Type command sudo certbot certonly --standalone
5. Your certificate will be downloaded and installed in /etc/letsencrypt folder

6. Your certificate files are as follows:
/etc/letsencrypt/live/<your domain name>/cert.pem
/etc/letsencrypt/live/<your domain name>/chain.pem
/etc/letsencrypt/live/<your domain name>/fullchain.pem
/etc/letsencrypt/live/<your domain name>/privkey.pem

7. Change permissions of these file if needed as it have default root access only so that Tomcat/ Tomee user can acces them

8. Type command sudo nano $CATALINA_BASE/conf/server.xml

9. Provide following lines in server.xml
<Connector port="443" protocol="org.apache.coyote.http11.Http11NioProtocol"
               maxThreads="150" SSLEnabled="true" >
        <UpgradeProtocol className="org.apache.coyote.http2.Http2Protocol" />
        <SSLHostConfig>
            <Certificate certificateKeyFile="/etc/letsencrypt/live/<your domain name>/privkey.pem"
                         certificateFile="/etc/letsencrypt/live/<your domain name>/cert.pem"
                         certificateChainFile="/etc/letsencrypt/live/<your domain name>/chain.pem"
                         type="RSA" />
        </SSLHostConfig>
    </Connector>

10.  // restart tomc(at/ee) server
11. Check your working https:// website in your domain name

Work Done

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If you have any doubts, please let me know.

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