Selected system manuals
Fifteen reference pages from Ubuntu 24.04, grouped by task. Each page keeps its source attribution. These are static snapshots; check the manual installed on your own machine before applying version-specific options.
Remote access
Start with the command, then look up persistent per-host options in the configuration reference.
- ssh(1)OpenSSH remote login client
- ssh_config(5)Client options, host patterns and connection settings
Services and logs
Use systemctl to inspect a unit, journalctl to read its logs, and systemd.service to understand the service definition.
- systemctl(1)Control the systemd system and service manager
- journalctl(1)Query the systemd journal
- systemd.service(5)Service types, startup behaviour and restart policy
DNS and local name resolution
dig queries DNS servers directly; resolvectl reports systemd-resolved's view. The hosts and resolv.conf references describe local mappings and resolver configuration.
- dig(1)Look up DNS records and inspect DNS replies
- resolvectl(1)Resolve names, addresses and DNS records
- resolv.conf(5)Resolver configuration and search domains
- hosts(5)Local host-name and address mappings
Interfaces, routes and sockets
Inspect addresses with ip, follow the routing decision with ip-route, and check listening or connected sockets with ss. Consult ufw before changing firewall policy.
- ip(8)Show and manipulate network configuration
- ip-route(8)Routing tables, route lookup and next-hop selection
- ss(8)Investigate sockets
- ufw(8)Uncomplicated firewall
Transfers and cryptography tools
curl covers HTTP requests and transfers. openssl is the entry point for its certificate, TLS and cryptography subcommands.