Linux from the command line | Linux for sysadmins -- Automating with SSH

Linux from the command line | Linux for sysadmins -- Automating with SSH

It's more than just a remote terminal tool, ssh has a lot of other powerful features for Linux users and sysadmins.

Once you get things in this article worked out, look up and play with ssh -Y

https://www.linuxjournal.com/content/easy-ssh-automation

Linux from the command line -- Checking disk space

Linux from the command line -- Checking disk space

One note here, with df you'll probably want to use "df -h" and not "df -H" as the latter will use the stupid damned si units nonsense where 1k=1000 bytes instead of a proper 1024.
Other than that, carry on.
https://www.linux.com/learn/intro-to-linux/2018/6how-check-disk-space-linux-command-line

Linux for sysadmins -- Removing Docker images, containers, and volumes

Linux for sysadmins -- Removing Docker images, containers, and volumes

So you're done with that Docker container. It served you well, but you don't need it any more. Now what?
https://www.tecmint.com/remove-docker-images-containers-and-volumes/#

Linux from the command line -- using the netstat command

Linux from the command line -- using the netstat command

What's going on with your Linux box's network?
https://www.howtoforge.com/linux-netstat-command/

Linux for sysadmins -- checking user groups

Linux for sysadmins -- checking user groups

The Linux user and group systems allow powerful, fine-grained access control to system applications, files, and resources. It's important to know how to list and manage user and group membership.

As an example, to use VirtualBox on Linux, users must be a member of the vboxusers group.
Other applications require a user to be a member of the group dialout.
https://www.2daygeek.com/how-to-check-which-groups-a-user-belongs-to-on-linux/#

Linux from the command line -- manipulating text file formatting with expand and unexpand

Linux from the command line -- manipulating text file formatting with expand and unexpand


The link is for the expand command. Find info on it's counterpart, unexpand, at this link: https://www.howtoforge.com/linux-unexpand-command/
https://www.howtoforge.com/linux-expand-command/

Linux for sysadmins -- Processes and process management for Linux

Linux for sysadmins -- Processes and process management for Linux
https://www.tecmint.com/linux-process-management/

Linux tips & tricks -- Managing multiple monitors with umonitor

Linux tips & tricks -- Managing multiple monitors with umonitor

The umonitor app basically lets you backup and restore multiple display configurations. An ability which you can use to switch between multiple monitors easily.
https://linoxide.com/linux-how-to/umonitor-update-positions-resolutions-monitors/

Linux for sysadmins -- Backing up and restoring MySQL databases with Mysqldump

Linux for sysadmins -- Backing up and restoring MySQL databases with Mysqldump

Backups are for more than just file systems, your databases need to be backed up too..

Linux from the command line -- Setting up Passwordless SSH Logins

Linux from the command line -- Setting up Passwordless SSH Logins

This is an important thing to know how to do and it makes your life much easier too. Once you learn this, you can expand this technique to use with less PC like devices. For example the ConnectBot app for your phone.

Learning Linux | Linux from the command line -- Useful Linux shortcuts

Learning Linux | Linux from the command line -- Useful Linux shortcuts

Here is a collection of everyday shortcuts that usually take a new user a long time to pick up the hard way.
https://linuxtechlab.com/informative-guide-to-useful-linux-shortcuts/

Linux from the command line -- Renaming multiple files at once

Linux from the command line -- Renaming multiple files at once

OK Grasshopper, time to learn a little basic command line kung-fu. By combining some simple commands along with some regular expression magic, you can perform some pretty complex operations quickly and easily.
https://www.ostechnix.com/how-to-rename-multiple-files-at-once-in-linux/

Display Calibration in Linux

Display Calibration in Linux

So yesterday I scored a new in box ColorVision Spyder2 at a garage sale for TWO BUCKS!!
I don't do any kind of for profit photo editing or anything, but I've always wanted a colorimeter to calibrate my displays and $2 is hard to pass up.
Basically a colorimeter is a device to measure the colour response of your display device. In concert with the appropriate software, you can then create a colour profile for the display. This allows your computer's colour management software to adjust what it outputs based on that colour curve in order to compensate for any deficiencies in your display and force it's output to be as accurate as possible. Why? Well, at a minimum so that what you see on the screen most closely matches the original image, but also so that when combined with a properly calibrated printer, what you print looks the same as what you see on the screen.

This device, being a little bit older model, doesn't work well with Windows 10. At least with the official, included software, but I don't care about that for several reasons. Not the least of which being I don't use Windows 10 at home. A bigger reason is that I found third party software that works on Windows, Linux, and Mac and so I used that instead.

The DisplayCal software creates calibration profiles in concert with, and for use by, the ArgyllCMS colour managament system.
You'll need to install both on your computer first.
I tested this all on my ThinkPad running OpenSUSE Linux LEAP 42.3.
This software isn't beginner level and a good RTFM is probably in order. However I managed to get it started on a profile run in a few minutes. The profile creation itself took a couple of hours and the results are impressive. ThinkPads are not content creation devices so they don't come with colour calibrated screens or high colour range screens. Despite that, once calibrated, the photo image quality is amazing. At least compared to stock.
I plan to run it on all my devices soon.

Meanwhile, if you get an opportunity to grab a good deal on a DisplayCal supported colorimeter, go for it.

https://displaycal.net/

Linux from the command line | Linux tips & tricks -- Everyday bash tips

Linux from the command line | Linux tips & tricks -- Everyday bash tips
https://opensource.com/article/18/5/bash-tricks

Linux from the command line -- Finding files with find

Linux from the command line -- Finding files with find

I've posted on "find" before but it's always worth repeating the basics.

Linux for sysadmins -- Getting started building a firewall with iptables

Linux for sysadmins -- Getting started building a firewall with iptables

Linux has firewall capabilities built in and the iptables tools are what you use to configure them.
https://www.rosehosting.com/blog/common-firewall-rules-and-commands-in-iptables/

Linux for sysadmins | Linux from the command line -- What version of Linux am I running?

Linux for sysadmins | Linux from the command line -- What version of Linux am I running?

This may sound like a ridiculous task, finding out what version and distro of Linux you're using, I mean you're sitting in front of it and you installed it!
Yes, it may be silly for home users, but for sysadmins and IT consultants, it's a common question. When you remote into a customer's system you may get no signs as to what type and version of system it is and you'll need to know that before you can diagnose and repair it effectively.
https://opensource.com/article/18/6/linux-version

Linux for sysadmins | Linux from the command line -- basic storage partitioning with parted

Linux for sysadmins | Linux from the command line -- basic storage partitioning with parted

These days parted is the defacto basic command line tool for examining, creating, and editing partitions on storage media. It's well worth learning.
Keep in mind though that these days most Linux distros have their own partitioning tool, at least for use during the installation process, if not from the administration interface.
https://opensource.com/article/18/6/how-partition-disk-linux

Linux from the command line -- the first network diagnostic command everyone ever learns -- ping

Linux from the command line -- the first network diagnostic command everyone ever learns -- ping

Of course everyone knows ping and how to operate it in it's default mode, but too many people don't learn it's other capabilities. ping is a powerful network diagnostic tool in it's own right and can be used in a lot of creative ways.
I used to use it with the -c option back in the dial-up days in order to cause the auto-connect system to dial up to our ISP and wait for it to show replies before continuing with cron jobs that required Internet access (eg time sync, system updates, etc.)
https://www.howtoforge.com/linux-ping-command/

Linux from the command line -- Using screen

Linux from the command line -- Using screen

I've posted on the screen command several times before, but it's a good tool and since everyone learns differently, it's good to have different sources of reference so here's another one.

Linux from the command line -- Comparing files and directories with diff

Linux from the command line -- Comparing files and directories with diff

Did all those files copy? Are these the same version of that document?
Find out that and more with diff.
https://www.networkworld.com/article/3279724/linux/comparing-files-and-directories-with-diff-and-comm.html

Linux for sysadmins -- Setting up Puppet on CentOS 7

Linux for sysadmins -- Setting up Puppet on CentOS 7

When you step up to the Enterprise level as a Linux sysadmin, you'll need to learn, install, configure, and use an administration system. A real one. That category has two sub-categories. Open Source tools, and commercial tools.
Both are worth learning.
https://www.howtoforge.com/tutorial/centos-puppet-master-and-agent/

Linux from the command line | Linux for sysadmins --- quick and easy e-book reading from the command line with...

Linux from the command line | Linux for sysadmins --- quick and easy e-book reading from the command line with Uniread

Before you discount the idea of command line ebook reading, imagine storing all your server software, hardware, and applications manuals on the server, ready to read from anywhere.
https://www.linuxuprising.com/2018/06/read-ebooks-quicker-with-this-spritz.html

Linux for sysadmins | Linux from the command line -- Who has that package for your Linux distro?

Linux for sysadmins | Linux from the command line -- Who has that package for your Linux distro?

whohas will find sources that carry a particular package. Remember though to always check your official distros first.
https://www.ostechnix.com/find-if-a-package-is-available-for-your-linux-distribution/

Linux for sysadmins -- Monitoring Apache Performance on CentOS 7 Using Netdata

Linux for sysadmins -- Monitoring Apache Performance on CentOS 7 Using Netdata

Running a webserver requires close monitoring to make sure you're not ticking off your customers with a slow website.
https://www.tecmint.com/monitor-apache-performance-using-netdata-on-centos/#

Linux for sysadmins -- Creating a Wildfly load-balancing cluster on Linux

Linux for sysadmins -- Creating a Wildfly load-balancing cluster on Linux
https://linuxtechlab.com/creating-wildfly-cluster-linux/

Linux from the command line -- Monitoring Docker

Linux from the command line -- Monitoring Docker

Just what are those containers up to? How much of your resources are they using?
https://kerneltalks.com/virtualization/docker-container-utilization-monitoring/

Linux from the command line | Linux for sysadmins -- modifying RPM packages with rpmrebuild

Linux from the command line | Linux for sysadmins -- modifying RPM packages with rpmrebuild

For those of you not in the Ubuntu cult, RPM packages may be a regular part of your Linux life, but nothing is perfect. What if you finally found an RPM package for that obscure piece of software you can't live without, but it's missing a file? Don't sweat it, fix it yourself.
https://linuxconfig.org/how-to-modify-an-rpm-package-using-rpmrebuild

Linux from the command line -- The sleep command

Linux from the command line -- The sleep command

Sometimes you need your system to wait before doing something, especially in a script. The sleep command is just what the penguin ordered.

There are plenty of uses outside of scripts too. Like when combined with the shutdown command.
https://www.howtoforge.com/linux-sleep-command/

Linux for sysadmins | Linux from the command line -- Security auditing with Lynis

Linux for sysadmins | Linux from the command line -- Security auditing with Lynis

Being proactive about security is one of the hallmarks of a good sysadmin. Security auditing and pen testing is part of that. From the early days with a handful of tools like SATAN and Metasploit to now when we have even more and better tools available, there's no excuse for not having a few in your toolbox and using them regularly. It's either that or end up on the news doing the walk of shame after getting fired because your company had a big data breach.
https://www.linuxtechi.com/lynis-security-auditing-tool-linux-servers/

Linux for sysadmins | Linux from the command line -- Testing a package without installing it using Nix

Linux for sysadmins | Linux from the command line -- Testing a package without installing it using Nix

I'm sure everyone can appreciate the ability to test or use some software without having to go through the hassle of installing it, not to mention dealing with the changes, and mess, that can make of your system. Nix lets Linux users avoid all that.

https://www.ostechnix.com/how-to-test-a-package-without-installing-it-in-linux/

Linux from the command line -- interactively killing Linux processes with fkill

Linux from the command line -- interactively killing Linux processes with fkill
https://www.tecmint.com/fkill-kill-linux-process-by-name-or-pid/

Linux for sysadmins | Linux from the command line -- Advanced drive usage and partitioning with LVM

Linux for sysadmins | Linux from the command line -- Advanced drive usage and partitioning with LVM

This article gives you the basics for using the powerful LVM tool in conjunction with multiple Linux file-systems. This is the basic command line method for the two basic Linux types, RH and Debian, and it's a good way for you to grasp the concepts. However keep in mind that most systems have other, preferred tools to perform these operations so RTFM for your Distro. OpenSUSE users, for example, should use the "Partitioner" module of the YaST2 administration tool to perform these functions.
https://www.linuxnov.com/create-lvm-partition-with-xfs-ext4-file-systems-on-rhel-and-debian/

Linux from the command line -- Pulling info out of proc with procinfo

Linux from the command line -- Pulling info out of proc with procinfo

Most of the system information you could ever want from your Linux system is ready and waiting for you in the proc folder. Remember, everything is a file in Linux (or at least it was until it was infected with systemd) so you can use simple tools like ls and cat to find and display this info in any way you wish. Throw in grep, sed, awk, and watch and you can create some pretty impressive output of your system's innards. However, for a quick and simple way to get the most commonly used data out, procinfo has you covered.
https://www.tecmint.com/procinfo-shows-proc-system-information/

Linux from the command line -- Organized task viewing with pstree

Linux from the command line -- Organized task viewing with pstree

https://www.howtoforge.com/linux-pstree-command/

Linux from the command line -- Using arrays in Bash

Linux from the command line -- Using arrays in Bash

The command line in Linux is more than just a dumb terminal. It's a powerful tool that you can program. It even includes arrays. Here's an introduction to those arrays.
https://opensource.com/article/18/5/you-dont-know-bash-intro-bash-arrays

Linux for sysadmins -- Installing Webmin on Debian 9

Linux for sysadmins -- Installing Webmin on Debian 9

Webmin is a great admin tool that allows you to do extensive administration tasks on a Linux system remotely using only a web browser. It not only handles basic system administration, but administration of applications and services like web servers, database servers, etc.

https://www.rosehosting.com/blog/how-to-install-webmin-on-debian-9/

Linux for sysadmins | Linux from the command line -- Monitoring servers with Glances

Linux for sysadmins | Linux from the command line -- Monitoring servers with Glances

Being a good sysadmin requires a lot of things, two of which are monitoring in order to spot trends which may indicate impending issues so you can head them off before they do, and diagnosis skills to find problems quickly when they do happen. Good monitoring tools and skills are a major part of achieving those two things.
Luckily Linux has a huge portfolio of monitoring tools available for every kind of task and resource. Glances is one of them.
http://www.linuxbuzz.com/monitor-linux-servers-glances-tool/

Linux from the command line -- Converting multiple media files at once with FFMPEG

Linux from the command line -- Converting multiple media files at once with FFMPEG

This article is a good example of the kinds of things you can do with a little command line knowledge.
https://linuxconfig.org/how-to-use-ffmpeg-to-convert-multiple-media-files-at-once-on-linux