| System Information | |
|---|---|
| OS Version (Ubuntu Version) | lsb_release -a |
| cat /etc/os-release | |
| Kernel Release Information | uname -a |
| Disk Usage | df |
| df -h | |
| Memory Usage | free |
| free -h | |
| Uptime | uptime |
| Who are logged in | w |
| System date and time | date |
| Hostname | hostname |
| Hardware Information | |
| List hardware | lshw |
| lshw -short | |
| List PCI devices | lspci |
| lspci -v | |
| List USB devices | lsusb |
| List SCSI devices | cat /proc/scsi/scsi |
| lsscsi (if lsscsi package is installed) | |
| Display device driver messages | dmesg |
| (Pipe to grep for specific info) | dmesg | grep -i usb |
| Process Management | |
| List all processes | top |
| List active processes | ps -ef |
| Kill a process with PID pid | kill pid |
| Kill with signal 9 if above doesn't work | kill -9 pid |
| List tree of processes | pstree |
| Which process is using file | fuser filename |
| Networking | |
| List network interfaces | ifconfig |
| ip addr show | |
| Show routing tables | ip route show |
| Configure an interface | Edit /etc/network/interfaces and restart networking |
| Restart Networking | systemctl restart networking |
| /etc/init.d/networking restart | |
| service networking restart | |
| List all ports | netstat -a |
| List all active listening ports | netstat -tupl |
| Service Management | |
| Start a service called myservice | /etc/init.d/myservice start |
| service myservice start | |
| Stop a service called myservice | /etc/init.d/myservice stop |
| service myservice stop | |
| Check status of a service called myservice | /etc/init.d/myservice status |
| service myservice status | |
| For newer versions with systemd instead of sysvinit above commands are | systemctl start myservice |
| systemctl stop myservice | |
| systemctl status myservice | |
| Logs | |
| General System Logs | /var/log/syslog |
| Kernel logs | /var/log/kern.log |
| Boot logs (sysvinit based older versions) | /var/log/boot.log |
| Boot logs (sysemd based newer versions) | journalctl -b |
| Kernel ring buffer log | /var/log/dmesg |
| Search | |
| Search for a file | find / -name filename |
| locate filename | |
| Search for a file in path /home/mydir | find /home/mydir -name filename |
| Search for all files greater than size 100MB | find / -size +100M |
| Suppress errors while using find or any command | 2>/dev/null |
| find / -size +100M 2>/dev/null | |
| Search for pattern in a file | grep pattern filename |
| Search for pattern in directory | grep -r pattern dirname |
| Package Management | |
| Install a package using apt | apt install <package-name> |
| apt-get install <package-name> | |
| Check for broken packages | apt-get check |
| Remove broken packages | apt autoremove |
| apt-get autoremove | |
| Refresh package list | apt update |
| apt-get update | |
| List upgradable packages | apt list --upgradable |
| Upgrade packages | apt upgrade |
| apt-get upgrade | |
| Uninstall a package | apt remove <package-name> |
| apt-get remove <package-name> | |
| Uninstall a package and remove config files | apt purge <package-name> |
| apt-get purge <package-name> | |
| Search for a package | apt search <package-name> |
| apt-cache search <package-name> | |
| Show package information | apt show <package-name> |
| apt-cache show <package-name> | |
| Install a package using dpkg | dpkg -i packagename.deb |
Note: apt is avaialable in newer versions as a more user-friendly alternative that merges several functions of apt-get and apt-cache. However this is not a proxy command and its output can change from one version to another. So use it in scripts with caution, especially if you are going to process the output of apt.
apt-get and apt-cache are lower-level backend and backward-compatible.
