Blog
Mert Özen's blog posts on software development, backend, frontend, and DevOps.
From Ubuntu 24.04 to 26.04 and Reading Old Servers: sudo-rs, Rust Coreutils, nftables, SysV to systemd
On Ubuntu 26.04 the command names stay the same, but sudo-rs and the Rust coreutils can change behavior: in the uutils 0.10.0 I tested, ln -sfn is no longer atomic and sudo's error message differs, so run your scripts on the new release before upgrading. We cover OpenSSH 10's post-quantum key exchange, SysV scripts, the equivalents of ifconfig and iptables, RHEL differences and choosing between an in-place upgrade and a new server, with real output.
Users, Groups and Permissions: rwx, chmod, chown, umask, sudo and Service Accounts
On Linux you run an application neither as root nor as your own user, but as a service user that belongs to it alone and cannot log in; for Bookstore that is a bookstore user, a separate deploy user that writes releases, and a secrets.env with mode 640. With real output we cover what rwx means on directories, chmod/chown/umask, setgid directories, the sticky bit, ACLs, a sudoers rule written with visudo that allows a single command, and the pitfalls of chmod 777 and sudo.