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CentOS Howtos and Tutorials

Centos Linux tutorial for beginners and advanced users with special focus on security, firewall, web, mail, file and proxy servers in an enterprise environment (rss feed).

Linux Check Disk Space Command

I recently switched from a Windows server to a Linux server operating system. I am using Ubuntu LTS server. How do I find out disk space utilization information using command line option?
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How To Patch and Protect Linux Kernel Zero Day Vulnerability CVE-2016-0728 [ 19/Jan/2016 ]

A very serious security problem has been found in the Linux kernel. A 0-day local privilege escalation vulnerability has existed since 2012. This bug affects millions of Android or Linux applications to escalate privileges. Any server or desktop (32 or 64 bit) with Linux Kernel version 3.8+ is vulnerable. How do I fix this problem?
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The OpenSSH project released an ssh client bug info that can leak private keys to malicious servers. A man-in-the-middle kind of attack identified and fixed in OpenSSH are dubbed CVE-2016-0777 and CVE-2016-0778. How do I fix OpenSSH's client vulnerability on a Linux or Unix-like operating system?
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How to list all iptables rules with line numbers on Linux

I recently added NAT rules on my RHEL 6.x system. How do I see the rules including line numbers that I just added in Linux?
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How to check boot path (partition) in Linux

How do I identify the boot device or boot path in Linux operating system?
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How to backup and restore a partition table on Linux

Is it possible to just backup my Linux partition table and restore it when required? How do I restore partition table if it get deleted by mistake on Linux operating system? How do I backup and restore a GPT partition table on Linux?
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How To Read CPUID Instruction For Each CPU on Linux With x86info and cpuid Commands

Is there a CPU-Z like a freeware/open source software that detects the central processing unit (CPU) of a modern personal computer in Linux operating system? How can I get detailed information about the CPU(s) gathered from the CPUID instruction, including the exact model of CPU(s) on Linux operating system?
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How to find out AES-NI (Advanced Encryption) Enabled on Linux System

The Intel Advanced Encryption Standard (AES) or New Instructions (AES-NI) engine enables extremely fast hardware encryption and decryption for openssl, ssh, vpn, Linux/Unix/OSX full disk encryption and more. How do I check support for Intel or AMD AES-NI is loaded in my running Linux in my Linux based system including openssl?
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How to summarize detailed system resource usage for given command on a Linux or Unix

How do I determine the system resource usage during of execution of a particular command on a Linux, OS X Unix, BSD and Unix-like operating system?
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How To See Characteristics of File Systems on Linux or Unix

How do I display the characteristics of file systems such as inodes, blocks, block size, file system name, state, lifetime writes, fsck status and more on Linux or Unix-like operating system?
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