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Novice Linux / Unix System Administrator Tutorials

These tutorials assumes that you have basic understanding of Unix like operating systems and you are familiar with – Unix/Linux and its commands at the user level, know how to edit files, familiar with the Bourne shell/Bash/Ksh shell, know how to perform standard file processing tasks (such as find/move/copy/delete/) and so on. ( rss feed )

How to upgrade OpenSSH 7.0 to 7.2 on a OpenBSD Unix and Linux

OpenSSH version 7.2 has been released. How do I install or upgrade my existing OpenSSH version to 7.2 on a OpenBSD unix operating system?
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How to run a command or script after running apt-get command on a Debian or Ubuntu Linux

How do I run custom command after ‘apt-get upgrade‘ or ‘apt-get dist-upgrade‘ on a Debian or Ubuntu Linux based system? How do I hook a script to apt-get command on my Ubuntu Linux server?
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A stack-based critical buffer overflow was found in the way the libresolv library (glibc) performed dual A/AAAA DNS queries. A remote attacker could crash or, potentially, execute code running the library on Linux. How do I patch and protect my server or workstation against the glibc getaddrinfo on Linux operating system?
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How to reload sysctl.conf variables on Linux

I am new Linux system user. How do I reload all sysctl variables without rebooting my server?
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Ubuntu sudo: add-apt-repository: command not found error and solution

I‘m trying to run a command ‘sudo add-apt-repository ppa:foo/bar‘ but getting the following error:

     sudo: add-apt-repository: command not found

How do I fix this problem on Ubuntu Linux 14.04 LTS server?
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FreeBSD find the chmod numerical value for a file or directory

I need to find out the numerical value of a file on a FreeBSD system. For example, get 644 instead of -rw-r--r-- for the /etc/resolv.conf file. Is there is a way to get this value in my bash shell script?
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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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