This post contains a collection of useful Linux commands for the Ubuntu distribution. The list is extended every time I find a new handy command. Most of the commands are also applicable to other Linux distributions.
File System Commands
Description
EXAMPLE
Display Current Working Directory
pwd
Change Current Working Directory
cd /path/to/directory
Show All Files in Current Directory (Including Hidden Ones)
ls -la
Show Sizes of All Files and Directories in Current Directory
du -sh *
Show Available Disk Space
df -h
Copy File
cp /source/file /destination/file
Move or Rename File
mv /source/file /destination/file
Create Directory
mkdir myDirectory
Delete File rm /path/to/file
Delete Directory Recursively rm -rf /path/to/directory
Create Symbolic Link
ln -s /path/to/target /path/to/symlink
Change File Permissions
sudo chmod 644 /path/to/file
Change Owner of Files / Directories (recursive)
sudo chown -R user:group /my/path
Show All Disks and Partitions
lsblk
Mount USB Stick
pmount /dev/sdf1
Unmount USB Stick
pumount /dev/sdf1
File System Commands
Viewing, Editing and Comparing Files
Description
Example
Display File Contents
cat /path/to/file
Edit File
sudo nano /path/to/file
View End of File
less +G /path/to/file
View End of File and Update Automatically
tail -f /path/to/file
Compare Files in Two Directories Recursively
diff -rq /path/to/dir1 /path/to/dir2
Viewing, Editing and Comparing Files
Package Management Commands
Description
Example
List Upgradable Packages
apt list --upgradable
Upgrade Installed Packages
sudo apt upgrade
List All Installed Packages
apt list --installed
Show Version of Installed Package
apt list <package name>
Package Management Commands
Network / Internet / Firewall Commands
Description
Example
Check Host Availability
ping [IP or hostname]
Download File
curl -O [URL]
List Open Ports
sudo lsof -i -P -n | grep LISTEN
Open Firewall to Specific Port from Local Subnet
sudo ufw allow from 192.168.1.0/24 to any port 22
Delete Firewall Rule by Number
sudo ufw status numberedsudo ufw delete 42
Network and Firewall Commands