Linux · Systems fluency
How is the Linux filesystem hierarchy organized?
Short answer
Linux presents one rooted tree starting at /. The Filesystem Hierarchy Standard assigns predictable purposes such as /etc for configuration, /var for variable data, /usr for system software, and /proc for kernel state.
Unlike drive letters, Linux mounts every filesystem somewhere under the single root. The hierarchy is a convention rather than a hard rule, but production tools and administrators depend on those conventions.
ls -1 /
ls -l /var/logThe directories you use most
- /etc: host-specific configuration files
- /var: logs, caches, spools, and other data that changes at runtime
- /usr: read-only system binaries, libraries, and shared data
- /home: interactive user home directories
- /tmp: temporary files, often cleaned on reboot
- /proc and /sys: virtual filesystems exposing kernel and device state
Separate partitions for /var, /home, or /tmp can contain growth and protect the root filesystem. On modern systems /bin, /sbin, and /lib are often symlinks into /usr as part of the usr-merge.
Follow-ups you should expect
Interviewers use these to check whether the first answer was understanding or memorisation.
- 1Why is /proc a virtual filesystem?
- 2What belongs in /etc versus /var?
- 3When would you put /var on its own partition?
- 4What is the usr-merge and why does it exist?
Say it in the interview
Linux uses one tree rooted at slash. Configuration goes in /etc, changing runtime data in /var, system software in /usr, and user files in /home. /proc and /sys are virtual filesystems the kernel exposes for process and device state. The layout is a convention, but tools and backup policies rely on it, so I keep application configuration in /etc and persistent data in /var.
Use this as a model, not a script. Saying it in your own words is what makes it survive follow-up pressure.
Related questions
Reading is step one
Now say it out loud.
Understanding an answer and delivering it under pressure are different skills. Rehearse this topic in a live Linux mock interview and get scored feedback on depth, clarity and confidence.