Interview Q&A / Linux & Shell
Linux & Shell interview questions
Permissions, processes, pipes and the commands you are expected to know cold.
Prefer rapid revision? Practise Linux & Shell short interview answers →
- How do you check whether a remote port is reachable from a Linux machine?
Use nc -zv host port for a quick TCP check, or curl -v telnet://host:port, or bash's /dev/tcp. A refused connection means nothing listens there; a timeout usually means a firewall or routing problem. ping only tests ICMP, not ports.
IntermediateQuick answer1 min read - What do the curl flags -s, -L, -o, -f and -I do?
-s hides the progress meter, -L follows redirects, -o saves the body to a file, -f makes curl fail with a non-zero exit code on HTTP errors, and -I fetches only the headers. A common combination in scripts is curl -fsSL.
IntermediateQuick answer1 min read - What is the difference between scp and rsync for copying files over SSH?
Both copy over SSH. scp sends the whole file every time, while rsync compares source and destination and sends only the differences, can resume, and can preserve permissions and delete extras. Use scp for one-off copies and rsync for repeated syncs and large folders.
IntermediateQuick answer1 min read