Systems fluency
Linux Interview Questions
Processes, permissions, networking, systemd, shells and the troubleshooting habits behind production Linux.
40 questions10 easy22 medium8 hard0/40 learned
01What is Linux?Easylinux · kernel · distributions02What is the difference between the kernel and the shell?Easykernel · shell · syscalls03How is the Linux filesystem hierarchy organized?Easyfilesystem · fhs · directories04How do Linux file permissions work?Mediumpermissions · chmod · security05How do chmod and chown work, and what are the risks?Mediumchmod · chown · permissions06How do Linux users and groups work?Easyusers · groups · identity07What is a process in Linux?Easyprocesses · fork · pid08How do process signals work, and when do you use which?Mediumsignals · sigterm · sigkill09How does shell job control work?Mediumjob-control · shell · background10How do you inspect processes with ps and top?Mediumps · top · monitoring11What is systemd and how does it work?Mediumsystemd · init · units12How do you manage services with systemctl?Mediumsystemctl · services · units13How do you read system logs and use journalctl?Mediumlogs · journalctl · debugging14How does Linux package management work?Easypackages · repositories · dependencies15How do apt and yum or dnf differ?Mediumapt · dnf · packaging16What are the Linux networking basics you need in production?Easynetworking · tcp · dns17How do you use ip and ss for network troubleshooting?Mediumiproute2 · ss · networking18How does DNS resolution work on Linux?Mediumdns · resolv.conf · nsswitch19How does SSH work and how do you use it safely?Mediumssh · remote-access · security20How do SSH keys work and how should they be managed?Mediumssh-keys · authentication · security21How do scp and rsync differ, and when do you use each?Mediumscp · rsync · file-transfer22How do you find files and content on Linux?Easyfind · locate · search23How do grep and regular expressions work?Mediumgrep · regex · logs24How do pipes and redirection work in the shell?Mediumpipes · redirection · file-descriptors25How do environment variables work on Linux?Easyenvironment · shell · configuration26How does cron work and what are its pitfalls?Mediumcron · scheduling · automation27How do you diagnose disk usage problems?Mediumdisk-usage · df · inodes28How does filesystem mounting work, including fstab and mount options?Hardmount · fstab · filesystems29How does Linux memory management work in production?Hardmemory · oom · page-cache30How does swap work and when should you use it?Mediumswap · memory · zram31What does load average mean, and how do you interpret it?Mediumload-average · cpu · monitoring32How do you approach Linux performance monitoring and diagnosis?Hardperformance · observability · profiling33How do you write a reliable shell script?Mediumbash · scripting · automation34How do you process text with awk, sed, and friends?Mediumawk · sed · text-processing35How do you create, inspect, and extract archives safely?Easytar · compression · backups36How do Linux firewalls work and how do you configure them safely?Hardfirewall · nftables · ufw37How do you harden a Linux server?Hardhardening · security · least-privilege38How do you troubleshoot a Linux production incident?Hardtroubleshooting · incident-response · debugging39How do containers work on Linux?Hardcontainers · namespaces · cgroups40What Linux operational best practices should a team follow?Hardoperations · automation · reliability
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