Linux is everywhere — servers, containers, cloud. The command line is your most powerful tool.

Navigation¶

pwd, ls -la, cd, mkdir -p, rmdir, tree

Files¶

cp, mv, rm, cat, less, head, tail, find, locate, wc

Text Processing¶

grep -r “pattern” .
sed ‘s/old/new/g’ file
awk ‘{print $1, $3}’ file
sort | uniq -c | sort -rn
cut -d, -f1,3 data.csv

Processes¶

ps aux, top/htop, kill, pkill, nohup, &, jobs, fg, bg

Permissions¶

chmod 755 file
chown user:group file
umask 022

Networking¶

curl, wget, ss, ping, traceroute, dig, nslookup, ip addr

Disk¶

df -h, du -sh, mount, fdisk, lsblk

Archives¶

tar -czf archive.tar.gz dir/
tar -xzf archive.tar.gz
zip -r archive.zip dir/
unzip archive.zip

Systemd¶

systemctl start/stop/restart/status service
journalctl -u service -f

Bash Scripting¶

!/bin/bash¶

set -euo pipefail

for file in *.log; do
echo “Processing $file”
gzip “$file”
done

Tip¶

Learn vim/nano, grep, awk and bash scripting. They’ll cover 80% of your needs.