Inspect Linux processes with ps, top, and pgrep
Compare a point-in-time process snapshot with live CPU and memory activity, then verify the owning command before taking action.
Read guide →LINUX · FIELD GUIDES
Linux administration guides
Practical Linux administration guides for processes, services, files, permissions, networking, packages, and shell operations.
Processes and services
Find and stop a Linux process safely
Identify a process, request graceful shutdown, and verify it exited before considering stronger signals.
Read guide →Manage Linux services with systemctl
Inspect a systemd unit, distinguish starting from enabling, and verify a deliberate service change.
Read guide →Inspect Linux service logs with journalctl
Filter systemd logs by unit and time, follow new entries, and preserve context around the first failure.
Read guide →Files and storage
Find large files and directories in Linux
Use du and find to locate space consumers while keeping the scan within the relevant filesystem.
Read guide →Check disk usage in Linux with df and du
Separate filesystem capacity from directory usage, and check inode availability as well as bytes.
Read guide →Files, permissions, and users
Understand Linux file permissions and ownership
Read owner, group, and mode bits; check directory traversal and ACLs; then make a narrow ownership or mode adjustment.
Read guide →Manage Linux users and groups safely
Inspect account records with getent and id, then make a narrowly scoped group change.
Read guide →Shell and operational basics
Find files with find and search text with grep
Search a bounded tree by name or content, and pass filenames safely when names may contain spaces.
Read guide →Use shell pipelines and redirection safely
Understand standard input/output, pipes, overwrites, quoting, pipeline status, and command exit codes in Bash.
Read guide →Write a small Bash script with safer error handling
Start scripts with explicit input checks, quoted variables, and predictable cleanup for temporary files.
Read guide →Work with environment variables, archives, and symbolic links
Inspect shell variables, create and safely inspect tar archives, and distinguish a symbolic link from its target.
Read guide →Networking
Inspect Linux network interfaces and IP addresses
Use iproute2 to inspect links, assigned addresses, and the route selected for a destination.
Read guide →Test connectivity with ping and curl
Separate ICMP reachability, DNS lookup, TCP connection, TLS negotiation, and HTTP response checks.
Read guide →Inspect listening ports and sockets with ss
List listening TCP and UDP sockets, check bind addresses, and identify process ownership when permitted.
Read guide →Diagnose Linux DNS with getent and dig
Compare application-style name service lookup with a direct DNS query, then inspect which service manages resolver settings.
Read guide →Software and scheduled operations
Install and update Linux packages with APT or DNF
Identify the distribution family, refresh package metadata, review proposed updates, and verify the installed software.
Read guide →Manage scheduled jobs with cron and systemd timers
Inspect a user crontab and systemd timers, then trace a missed job through its command, environment, and logs.
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