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Debian / Ubuntu

How to pair Pi-hole with an OpenVPN to block ads and increase privacy on Ubuntu / Debian Linux

I followed your tutorial to install an OpenVPN on my Ubuntu server in the cloud. How can I install Pi-hole to block ads, reduced my 4G/3G/LTE traffic on the same Debian or Ubuntu Linux server?
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Sysadmin because even developers need heroes!!!

How to add to bash $PATH permanently on Linux

I am a new Linux and bash shell user. How do I permanently set $PATH on Linux? How can I permanently add a directory to shell PATH on Linux?
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How to check if port is in use on Linux or Unix

How do I determine if a port is in use under Linux or Unix-like system? How can I verify which ports are listening on Linux server?
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How to run commands on Linux Container (LXD) instance at provision launch time

I would like to perform common automated configuration tasks and run commands/scripts after the LXD instance starts. How to use cloud-init to run commands on my Linux Container (LXD) instance at launch time?
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How to automatically mount zfs file system on Linux/Unix/FreeBSD

I have created a zfs file system called data/vm_guests on Ubuntu Linux server. After the server reboot, zpools do not automatically mount at /data/vm_guests. It is failing my KVM guest machines. How can I mount my ZFS (zpool) automatically after the reboot?
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How to delete KVM VM guest using virsh command

I am a new Linux and KVM user. How do I delete a VM guest with virsh command line on Linux operating system? How do I delete a virtual machine called vps42 on Ubuntu or CentOS Linux server?
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How to install PHP 7 on Debian Linux 8.6/7.x [jessie/wheezy]

I wanted to use PHP 7 on Debian 8.x. How do I install and configure PHP 7 on Debian Linux 8.x server? How do I install PHP 7 on Debian Linux 7.x “wheezy” VPS server hosted in cloud?
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A very serious security problem has been found in the Linux kernel. A 0-day local privilege escalation vulnerability has existed for eleven years since 2005. This bug affects all sort of of Android or Linux kernel to escalate privileges. Any user can become root in less than 5 seconds. The bug has existed since Linux kernel version 2.6.22+. How do I fix this problem?
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How to create snapshot in Linux KVM VM/Domain

Before upgrading my virtual machine, I would like to make a snapshot. I want to revert a domain/VM to a snapshot if something goes wrong with my upgrade. Is there a command to create a snapshot of virtual machine (VM) while it is running? Does qemu-kvm support live snapshot creation?
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How to force users to use secure passwords on Ubuntu/Debian Linux

My Linux shell user can modify their password using the passwd command. How can I force users to choose the secure password that will prevent users from using stupid passwords like “abc123”, “password”, “123456” and so on? How do I setup password quality requirements on my Debian or Ubuntu Linux server?
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