Thought I would share some commands I genuinely use all the time. Not the usual “top 10 linux commands” listicle stuff — these are the ones that have actually saved me time repeatedly.
Find what is eating your disk space (human-readable, sorted):
du -h --max-depth=1 /var | sort -hr | head -20
Watch a log file with highlighting for errors:
tail -f /var/log/syslog | grep --color -E "error|warn|fail|$"
The |$ trick highlights your keywords while still showing all lines.
Quick port check without installing nmap:
: </dev/tcp/192.168.1.1/22 && echo open || echo closed
Pure bash, no extra tools needed.
Find files modified in the last hour (great for debugging):
find /etc -mmin -60 -type f
Kill everything on a specific port:
fuser -k 8080/tcp
Quick HTTP server from any directory:
python3 -m http.server 8000
Everyone knows this one, but I still see people installing nginx for quick file transfers.
Check SSL cert expiry from the command line:
echo | openssl s_client -servername example.com -connect example.com:443 2>/dev/null | openssl x509 -noout -dates
What are your go-to one-liners? Always looking to add to my toolkit.
Ncdu is way better than dealing with du, it’s worth installing instead of sticking to built ins.
Good call on ncdu. I use it all the time for finding what’s eating disk space. The interactive TUI is way faster than piping du through sort. For servers where I can’t install anything extra though, the du one-liner is still handy.