First 50 Ubuntu Commands Every Administrator Should Know

First 50 Ubuntu Commands Every Administrator Should Know

These 50 commands cover the core operations you will perform daily on Ubuntu servers: checking system state, navigating the filesystem, managing files and processes, controlling services, and investigating network issues. Each command includes a practical example you can run immediately in a terminal.

System information

These commands answer the first questions when you sit down at an unfamiliar server: what is it running, who am I, and how long has it been up.

uname -a
hostnamectl
lsb_release -a
uptime
whoami
id
date
timedatectl

File system navigation

These commands let you orient yourself in the filesystem, find files, and check how much disk space is used.

pwd
ls -la /etc
cd /var/log
find /var/log -name "*.log" -mtime -1
df -h
du -sh /var/log/*

File operations

Creating, copying, moving, and archiving files are the most frequent file system tasks on a server.

# Copy a config directory
cp -r /etc/nginx /tmp/nginx-backup

# Create a timestamped archive
tar -czf /tmp/etc-backup-$(date +%F).tar.gz /etc

# Extract to a specific directory
tar -xzf backup.tar.gz -C /tmp/restore/

Reading file content

Reading log files and configuration files is one of the most common daily tasks for an Ubuntu administrator.

# Show last 100 lines of auth log
tail -n 100 /var/log/auth.log

# Follow syslog in real time
tail -f /var/log/syslog

# Search for failed login attempts
grep "Failed password" /var/log/auth.log

# Count how many times an IP appears in a log
grep "192.168.1.100" /var/log/nginx/access.log | wc -l

Permissions and ownership

Understanding and setting file permissions is critical for both security and functionality on Ubuntu servers.

# Make a script executable by owner only
chmod 700 /usr/local/bin/myscript.sh

# Set web root ownership to www-data
chown -R www-data:www-data /var/www/html

# View full permission details
stat /etc/passwd

# Check permissions in octal format
stat -c "%a %n" /etc/sudoers

Process management

Finding which processes are running and stopping ones that are misbehaving are regular server administration tasks.

# Find PID of a process
ps aux | grep sshd

# Kill a stuck process
kill -9 $(pgrep -f stuck-process)

# Show top 10 memory-consuming processes
ps aux --sort=-%mem | head -11

# Show processes owned by a user
ps -u www-data

Services and logs

Ubuntu uses systemd for service management. These commands cover the full service lifecycle and log inspection.

# Check all failed services
systemctl --failed

# See service logs since last boot
journalctl -b -u nginx

# Show last 50 error-level messages from any service
journalctl -p err -n 50 --no-pager

# Check if a service is enabled at boot
systemctl is-enabled ssh

Networking

These commands cover IP address inspection, open port discovery, connectivity testing, and DNS resolution.

# Show IP addresses
ip a

# List all listening ports and owning services
ss -tulpn

# Test DNS resolution
nslookup google.com

# Check what process is using port 443
ss -tulpn | grep :443

# Test HTTP response from a server
curl -I http://localhost

Practice checklist

Work through this checklist on a fresh Ubuntu VM to build muscle memory with the 50 commands above:

• Check system info: run commands 1–8 and note the output on your test VM.
• Navigate the filesystem: explore /etc, /var/log, and /home using ls -la and cd.
• Find files: use find to locate all .conf files under /etc.
• Check disk usage: identify which directory under /var is using the most space.
• Read a live log: use tail -f on /var/log/syslog while triggering a login in another window.
• Manage a service: stop, start, and check the status of ssh.
• Inspect ports: identify which process is listening on port 22.
• Search file content: grep /var/log/auth.log for your own username.

Summary

These 50 commands cover the daily reality of Ubuntu server administration. Start with system information commands to orient yourself, use file navigation and content commands for investigation, control services with systemctl and journalctl, and use networking commands to diagnose connectivity. The most important habit is reading the output of every command carefully rather than just running it and moving on.