This book is a collection of notes and sample codes written by the author while he was learning Linux applications. Topics include using managing users and groups; managing files and directories; managing Apache HTTP Server and Apache Tomcat; managing MySQL server and SquirrelMail server; running Python and PHP scripts; using OpenJDK for Java programs; using GCC C/C++ compilers; running graphical applications on GNOME desktop and X11 servers; running Conda - Environment and Package Manager. Updated in 2024 (Version v1.03) with OpenJDK Tutorials. For latest updates and free sample chapters, visit https://www.herongyang.com/Linux-Apps.