Linux Essentials for DevOps

Why Linux First?

Almost every server, container, and CI runner you will ever touch runs Linux. Master the terminal and everything else in DevOps becomes easier.

Navigating the Filesystem

pwd           # where am I?
ls -la        # list everything, including hidden files
cd /var/log   # jump to a directory
find . -name "*.log"   # find files by pattern

File Permissions

Permissions are the classic interview topic — and a daily reality:

ls -l app.sh
# -rwxr-xr--  owner can read/write/execute, group can read/execute, others read

chmod 755 app.sh   # rwx r-x r-x
chown deploy:deploy app.sh

Processes and Services

ps aux | grep nginx     # find a process
top                     # live resource usage
systemctl status nginx  # service status
journalctl -u nginx -f  # follow service logs

Practice Task

SSH into any Linux box (or open WSL) and:

1. Create a directory structure for a fake app: mkdir -p app/{logs,config,data}
2. Create a script that writes the date to a log file every run
3. Make it executable and run it with ./

Next lesson: Docker fundamentals — where these skills start paying off.