A quick, organized reference to the most-used Linux commands for managing your server. Bookmark this page.

Navigation & directories

pwd                 # print current directory
ls -lah             # list all files (long, human sizes)
cd /var/www         # change directory
cd ..               # up one level
mkdir -p a/b/c      # create nested directories
rmdir dir           # remove empty directory

File operations

cp file.txt bak.txt     # copy
cp -r dir1 dir2         # copy directory
mv old.txt new.txt      # move / rename
rm file.txt             # delete file
rm -r dir               # delete directory
touch file.txt          # create empty file
ln -s target linkname   # symbolic link

Viewing & editing files

cat file.txt            # print contents
less file.txt           # scroll (q to quit)
head -n 20 file.txt     # first 20 lines
tail -n 20 file.txt     # last 20 lines
tail -f app.log         # follow a log live
nano file.txt           # simple editor

Permissions & ownership

chmod 755 script.sh         # rwxr-xr-x
chmod +x script.sh          # make executable
chown user:group file       # change owner:group
chown -R www-data: /var/www # recursive
sudo command                # run as root

Processes & system

ps aux                  # all processes
top                     # live process monitor
kill 1234               # terminate by PID
kill -9 1234            # force kill
killall nginx           # kill by name
uname -a                # kernel / OS info
whoami                  # current user
uptime                  # load & uptime

Disk & memory

df -h                   # disk space per filesystem
du -sh /var/www         # size of a directory
free -h                 # memory usage

Searching & text

grep "error" app.log        # search text in a file
grep -ri "todo" .           # recursive, case-insensitive
find / -name "*.conf"       # find files by name
sort file.txt | uniq        # sort & de-duplicate
ps aux | grep php           # pipe + filter

Networking

ping example.com            # test connectivity
curl -I https://site.com    # fetch headers
wget https://site/file.zip  # download a file
ss -tlnp                    # listening ports
ssh user@server-ip          # remote login

Package management

# Debian/Ubuntu
sudo apt update && sudo apt upgrade -y
sudo apt install nginx
sudo apt remove nginx

# RHEL/AlmaLinux/CentOS
sudo dnf install nginx
sudo dnf remove nginx

Users

sudo adduser alice          # create user
sudo usermod -aG sudo alice # add to sudo group
sudo passwd alice           # set password
sudo deluser alice          # remove user

Archiving & compression

tar -czvf site.tar.gz /var/www   # create .tar.gz
tar -xzvf site.tar.gz            # extract .tar.gz
zip -r site.zip /var/www         # create .zip
unzip site.zip                   # extract .zip

For managing background services (start, stop, enable at boot), see “How to List and Manage Linux Services with systemctl” in this category.