IT Trends

Linux Cheatsheet for DevOps Engineers

1. File & Directory Operations

ls
ls -l
ls -a
ls -lh
cd /path/to/dir
cd ..
cd ~
touch filename
mkdir dir_name
rm filename
rm -rf dir_name
cp source destination
mv source destination
mv oldname newname
find /path -name filename
find /path -type f
      

2. File Permissions

ls -l filename
chmod 755 filename
chmod +x filename
chmod -x filename
chown user:group filename
      

3. Process Management

ps aux
ps -ef
kill PID
kill -9 PID
top
htop
command &
jobs
fg %1
      

4. System Monitoring

df -h
du -sh /path/to/dir
free -h
uptime
ifconfig
ip a
netstat -tuln
ss -tuln
      

5. Package Management

Debian/Ubuntu:
sudo apt update
sudo apt upgrade
sudo apt install pkg
sudo apt remove pkg
sudo apt search pkg

RedHat/CentOS:
sudo yum update
sudo yum install pkg
sudo yum remove pkg
sudo yum search pkg

Check installed packages:
dpkg -l
rpm -qa
      

6. Networking and SSH

ssh username@hostname_or_ip
ssh -i /path/to/key username@hostname_or_ip
scp local_file username@hostname:/path/to/destination
scp username@hostname:/path/to/source local_file
ssh-keygen -t rsa -b 2048 -f ~/.ssh/id_rsa
      

7. Logs and System Diagnostics

tail -f /var/log/syslog
tail -n 100 /var/log/syslog
grep "keyword" /var/log/syslog
dmesg
journalctl
      

8. User Management

sudo useradd username
sudo passwd username
sudo userdel username
sudo userdel -r username
sudo usermod -aG groupname username
cat /etc/passwd
      

9. Archiving and Compression

tar -cvf archive.tar directory
tar -czvf archive.tar.gz directory