Show system information:
uname -r
See kernel release information:
uname -a
Display how long the system has been running, including load average:
uptime
See system hostname:
hostname
Show the IP address of the system:
hostname -i
List system reboot history:
last reboot
See current time and date:
date
Query and change the system clock with:
timedatectl
Show current calendar (month and day):
cal
List logged in users:
w
See which user you are using:
whoami
Show information about a particular user:
finger [username]
Disk Usage
You can use the df and du commands to check disk space in Linux.
See free and used space on mounted systems:
df -h
Show free inodes on mounted filesystems:
df -i
Display disk partitions, sizes, and types with the command:
fdisk -l
See disk usage for all files and directory:
du -ah
Show disk usage of the directory you are currently in:
du -sh
Display target mount point for all filesystem:
findmnt
Mount a device:
mount [device_path] [mount_point]
SSH Login
Connect to host as user:
ssh user@host
Securely connect to host via SSH default port 22:
ssh host
Connect to host using a particular port:
ssh -p [port] user@host
Connect to host via telnet default port 23:
telnet host