🔐 Linux Permissions Every DevOps Engineer Should Know

The article explains Linux file and directory permissions, including how to read `ls -l` output and interpret mode bits.

It shows how to change access with `chmod` using both symbolic and numeric notation, plus related tools like `chown` and `sudo`.

It highlights why permissions matter for SSH private keys, application files, containers, and CI/CD pipelines.

It also introduces basic troubleshooting tools such as `grep`, `find`, and command redirection to help diagnose access errors faster.