Linux system administration involves managing and maintaining Linux systems to ensure they run efficiently, securely, and reliably. It includes managing user accounts by creating, modifying, and deleting them, as well as setting permissions and group memberships using commands like adduser, passwd, and usermod. Administrators manage the file system by monitoring disk usage, mounting/unmounting file systems, and setting file permissions with tools like chmod, chown, df, and mount.
Process management involves monitoring and controlling system processes using commands such as ps, top, kill, and systemctl for managing services. Package management ensures software is installed, updated, or removed as needed using package managers like apt for Debian-based systems or yum/dnf for Red Hat-based distributions. Network configuration involves setting up IP addresses, troubleshooting connectivity, and managing open ports using tools like ip, ping, and netstat.
Security management focuses on configuring firewalls with tools like ufw or iptables, managing SSH access, and applying updates to secure the system. Backups are handled using tools like rsync, tar, and scheduled with cron, ensuring data is safe and recoverable. Administrators monitor logs stored in directories like /var/log using commands like cat and journalctl and use logrotate to manage log file sizes.
Automation and scripting are integral, with repetitive tasks automated using Bash scripts and scheduled via cron. Performance monitoring is conducted with tools like top, htop, and vmstat to track resource usage and optimise performance. System and kernel updates are applied using package managers, followed by reboots if necessary.
Best practices include documenting changes, regularly applying updates, maintaining backups, minimizing root access through sudo, and continuously monitoring systems with tools like Nagios or Prometheus. Mastering these tasks forms the foundation of effective Linux system administration.