1. SSH, Remote Access, and File Transfer
The Secure Shell (SSH) is the workhorse for remote Linux administration, and almost every aspect of it can be customized. The per-user ~/.ssh/config file lets administrators define...
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The Secure Shell (SSH) is the workhorse for remote Linux administration, and almost every aspect of it can be customized. The per-user ~/.ssh/config file lets administrators define...
Read full chapter →DNS is the addressing layer of the internet, and Linux administrators must understand its record types. An A record maps a domain to an IPv4 address, AAAA to IPv6, and CNAME create...
Read full chapter →Modern Linux distributions manage services through systemd, and a small set of systemctl verbs covers most needs. systemctl start, stop, and restart control running state, while re...
Read full chapter →User account information is split across three traditional files: /etc/passwd (usernames, UIDs, GIDs, home, shell), /etc/shadow (password hashes and aging, readable only by root),...
Read full chapter →Linux exposes block devices through a virtual filesystem populated by udev, the kernel's device manager that creates entries under /dev dynamically as hardware appears and disappea...
Read full chapter →Modern Linux networking is configured with the ip family of commands. ip addr shows interfaces with their addresses and state; ip addr add IP/PREFIX dev IFACE assigns one, ip addr...
Read full chapter →The two leading open-source web servers on Linux are nginx and Apache. nginx configuration lives in /etc/nginx/nginx.conf with site definitions under sites-available/ and sites-ena...
Read full chapter →Process inspection starts with ps (for example, ps aux --sort=-%mem for top memory users and ps -ejH for hierarchy) and pstree -p for a tree view. pgrep returns PIDs matching a nam...
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