4.4Operations and practice

Automation scripts and CI jobs ultimately run on a shell (bash). So reading precisely "what this command sequence does" is basic fitness for deployment and operations. At the same time, DevOps is not a particular tool name but the culture and practice of breaking down the wall between development and operations to deliver fast and safely through automation and measurement. This section organizes basic bash operations and environment-variable handling as reading, and DevOps principles as the judgment of "why they create value."

4.4.1File and directory operations

• Where am I and what is here: pwd (print the current directory), ls (list contents, ls -l for detail, ls -a to include hidden files), cd path (move, cd .. goes up one). Mistaking where you are shifts how relative paths resolve, so it is safe to check your location with pwd first.
• Create, copy, move, delete: mkdir dir (make a directory, mkdir -p a/b/c creates parents too), cp src dst (copy, cp -r for directories), mv src dst (move or rename), rm file (delete, rm -r dir recursively). cat file prints a file's contents. rm -r is irreversible, so confirm the target before running it.