df -hsystemd-nspawn
blkid
gdisk -l /dev/path
fdisk -l
partprobe /dev/path
parted -l

Show Attached Hardware
lshw -class disk

Add a port
firewall-cmd –permanent –add-port=8081/tcp
firewall-cmd –add-port=8081/tcp
firewall-cmd –reload

Ubuntu:
ufw
iptables

Red Hat/Fedora:
firewalld/firewall-cmd
Configuration files location:
/etc/firewalld/

iptables

example to schedule an update followed up with a reboot:at 7:00 AM/usr/bin/yum update -y ; shutdown -r now^dOutput:job 1 at 2019-01-16 07:00 AM
List jobsatq
Display job commandat -c 1
Remove a jobatrm 1
Scheduling examples:Examples of at Command:Example 1: Schedule task at coming 10:00 AM.
 at 10:00 AM
Example 2: Schedule task at 10:00 AM on coming Sunday.
 at 10:00 AM Sun
Example 3: Schedule task at 10:00 AM on coming 25’th July.
 at 10:00 AM July 25
Example 4: Schedule task at 10:00 AM on coming 22’nd June 2015.
 at 10:00 AM 6/22/2015 at 10:00 AM 6.22.2015
Example 5: Schedule task at 10:00 AM on same date at next month.
 at 10:00 AM next month
Example 6: Schedule task at 10:00 AM tomorrow.
 at 10:00 AM tomorrow
Example 7: Schedule task at 10:00 AM tomorrow.
 at 10:00 AM tomorrow
Example 8: Schedule task to execute just after 1 hour.
 at now + 1 hour
Example 9: Schedule task to execute just after 30 minutes.
 at now + 30 minutes
Example 10: Schedule task to execute just after 1 and 2 weeks.
 at now + 1 week at now + 2 weeks
Example 11: Schedule task to execute just after 1 and 2 years.
 at now + 1 year at now + 2 years
Example 12: Schedule task to execute at mid night.
 at midnight
Example of executing a script fileat -m 01:35 < patching

Add user to sudoers
echo “user2 ALL=NOPASSWD: ALL” | tee -a /etc/sudoers.d/user2

Run Command
/bin/su -c ‘sudo nohup /df -h &’ user2