Part 3 - Summary of Common Linux Commands (Ubuntu)
Linux is the foundational OS for operations, development, cloud, containers, automation, and AI engineering. This article summarizes common and practical Linux commands for Ubuntu users.
Preface
Linux is the foundational operating system for operations, development, cloud computing, containers, automation, and AI engineering practices. For users working with Ubuntu, mastering common commands is essential for daily operations, system administration, and troubleshooting;
This article compiles a summary of common and practical Linux commands, suitable for daily learning and reference.
Commands
Directory and File Operations
View current directory
pwdView files in directory
lsView detailed information
ls -lShow hidden files
ls -laChange directory
cd /etc
cd ..
cd ~Create directory
mkdir test
mkdir -p /data/test/logsCreate empty file
touch test.txtCopy file
cp a.txt b.txtCopy directory
cp -r dir1 dir2Move/Rename file
mv old.txt new.txt
mv file.txt /tmp/Delete file
rm file.txtDelete directory
rm -r testdirForce delete
rm -rf testdirFile Viewing Commands
View file content
cat file.txtView with pagination
less file.txtView first 10 lines
head file.txtView first 20 lines
head -n 20 file.txtView last 10 lines
tail file.txtView logs in real-time
tail -f /var/log/syslogFile Search and Find
Find file
find / -name nginx.confFind txt files in current directory
find . -name "*.txt"Find directory
find /data -type d -name logsFind command path
which python3
which dockerSearch keyword in file
grep "error" app.logCase-insensitive search
grep -i "error" app.logShow line numbers
grep -n "error" app.logRecursive search in directory
grep -rn "listen" /etc/nginx/User and Permission Management
View current user
whoamiView logged-in users
whoSwitch user
su - rootExecute command with sudo
sudo apt updateChange file permissions
chmod 644 file.txt
chmod 755 script.shChange file owner
chown user:user file.txtRecursively change directory permissions
chmod -R 755 /data/testRecursively change owner
chown -R ubuntu:ubuntu /data/testSystem Information View
View system version
cat /etc/os-releaseView kernel version
uname -rView hostname
hostnameView CPU information
lscpuView memory information
free -hView disk usage
df -hView directory size
du -sh /dataView block devices
lsblkProcess Management
View current processes
ps -efFind specific process
ps -ef | grep nginxView processes dynamically
topMore friendly process view tool
htopKill process
kill 1234Force kill process
kill -9 1234Kill process by name
pkill nginxNetwork Related Commands
View IP address
ip aView routing table
ip routeTest network connectivity
ping 8.8.8.8Test domain resolution
ping www.baidu.comView port listening
ss -tunlpView specific port
ss -tunlp | grep 80View network connections
netstat -tunlpTest port connectivity
telnet 192.168.1.10 22Test HTTP service with curl
curl http://127.0.0.1
curl -I http://127.0.0.1Download file
wget https://example.com/file.tar.gzPackage Management (Ubuntu)
Update package source
sudo apt updateUpgrade packages
sudo apt upgrade -yInstall software
sudo apt install nginx -yUninstall software
sudo apt remove nginx -yComplete uninstall
sudo apt purge nginx -yAuto clean unused packages
sudo apt autoremove -ySearch package
apt search dockerService Management (systemd)
View service status
systemctl status nginxStart service
sudo systemctl start nginxStop service
sudo systemctl stop nginxRestart service
sudo systemctl restart nginxReload configuration
sudo systemctl reload nginxSet auto-start on boot
sudo systemctl enable nginxDisable auto-start on boot
sudo systemctl disable nginxView boot logs
journalctl -bView specific service logs
journalctl -u nginx -fCompression and Decompression
Pack as tar
tar -cvf archive.tar test/Unpack tar
tar -xvf archive.tarPack and compress as tar.gz
tar -zcvf archive.tar.gz test/Decompress tar.gz
tar -zxvf archive.tar.gzCompress zip
zip -r test.zip test/Decompress zip
unzip test.zipDisk and Mounting
View disk partitions
fdisk -lView file system usage
df -hMount disk
mount /dev/sdb1 /mntUnmount disk
umount /mntView UUID
blkidEditor Related
Edit file with vim
vim test.txtEdit file with nano
nano test.txtUser Management
Create user
sudo useradd -m testuserSet password
sudo passwd testuserDelete user
sudo userdel -r testuserView user information
id testuserSSH Remote Connection
Remote login
ssh user@192.168.1.100Connect with specific port
ssh -p 2222 user@192.168.1.100Copy file to remote server
scp file.txt user@192.168.1.100:/tmp/Copy file from remote server to local
scp user@192.168.1.100:/tmp/file.txt ./Common Log Paths (Ubuntu)
System logs
/var/log/syslogAuthentication logs
/var/log/auth.logKernel logs
/var/log/kern.logDPKG installation logs
/var/log/dpkg.logView log example
tail -f /var/log/syslog
tail -f /var/log/auth.logCommon Combined Commands
Find who occupies a specific port
ss -tunlp | grep 8080Find a specific process
ps -ef | grep pythonView large files/directories
du -sh * | sort -hrView recently modified files
ls -ltRun program in background
nohup python3 app.py > app.log 2>&1 &View background jobs
jobsLinux Learning Suggestions
For Ubuntu beginners, there is no need to memorize all commands at once. It is more important to understand several core directions:
- How to operate files and directories
- How to manage services
- How to view processes
- How to troubleshoot network issues
- How to view logs
- How to install software
- How to handle permissions
Once these high-frequency commands are mastered, whether doing Linux operations, Docker, Kubernetes, or AI development and service deployment, it will be much easier.