Linux for sysadmins -- Blocking locally spoofed addresses

Linux for sysadmins -- Blocking locally spoofed addresses
https://opensource.com/article/18/2/block-local-spoofed-addresses-using-linux-firewall

Linux tips & tricks -- 5 tools for data rescue

Linux tips & tricks -- 5 tools for data rescue

One of the most powerful IT tools I carry with me is a multi-boot USB stick with multiple Linux distributions and other tools on it. It can be an absolute lifesaver for emergency diagnostics, repair, and recovery.
Of these tools I've used ddrescue and photorec many times with impressive results.

One other thing you should carry in your IT toolbag, a reasonably large blank external USB (pref 3.0 these days) hard drive. Why? To recover data to, and to work on. There are many circumstances where recovering and repairing data in place is a bad idea, for example on a failing hard drive. In this case you use ddrescue to pull an image of the failing drive into an image file on the external drive (make sure is is formatted with a file system that can handle LARGE files. IE not FAT32) and then you perform your recovery operation on the image file instead of the original drive. There may even be circumstances where having a second USB drive to recover to is necessary. In other words a well stocked IT dept probably contains several multi-TB external USB drives and a few USB sticks with multi-boot tools.
https://www.maketecheasier.com/recover-data-linux-tools/

Linux from the command line -- Installing nVidia drivers on Debian

Linux from the command line -- Installing nVidia drivers on Debian
https://linuxconfig.org/how-to-install-the-latest-nvidia-drivers-on-debian-9-stretch-linux

Linux from the command line | Linux for sysadmins -- ctop. top for containers

Linux from the command line | Linux for sysadmins -- ctop. top for containers
https://www.2daygeek.com/ctop-a-command-line-tool-for-container-monitoring-and-management-in-linux/

Linux from the command line -- Mish mash of command line productivity

Linux from the command line -- Mish mash of command line productivity
https://opensource.com/article/18/2/getting-to-done-agile-linux-command-line

Linux from the command line -- screen again

Linux from the command line -- screen again

I've posted on screen before. Here it is again because more examples are always a good thing.
http://linuxtechlab.com/learn-use-screen-command-examples/

Linux from the command line - who's on first

Linux from the command line - who's on first


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

Linux tips & tricks -- Installing snapd on various Linux distros

Linux tips & tricks -- Installing snapd on various Linux distros

https://itsfoss.com/install-snap-linux/

Linux from the command line -- Recursion -r or -R?

Linux from the command line -- Recursion -r or -R?

Unfortunately some daft tit developers at some point came along and ignored previous commands and did their own thing as to using -R vs -r so here we are. The rule is now about like most of the rules of the English language.
Oh well, here you go.

TIP - Try -R first if you're not sure.
https://www.networkworld.com/article/3256288/linux/linux-to-recurse-or-not.html

Linux from the command line -- Running a command for a specified time

Linux from the command line -- Running a command for a specified time
https://www.ostechnix.com/run-command-specific-time-linux/

Linux for sysadmins -- Forcing users to change their passwords

Linux for sysadmins -- Forcing users to change their passwords

Make the lazy troglodytes you're forced to take care of change their passwords. ;')
https://www.tecmint.com/force-user-to-change-password-next-login-in-linux/#

Linux from the command line -- Using FFMPEG to convert media files

Linux from the command line -- Using FFMPEG to convert media files
https://www.maketecheasier.com/ffmpeg-commands-media-file-conversions/

Linux LAN Routing

Linux LAN Routing

Want a router that doesn't need a support subscription or that the government hasn't hacked? Build your own with Linux.
https://www.linux.com/learn/intro-to-linux/2018/2/linux-lan-routing-beginners-part-1

Linux from the command line -- The bare essentials, start here

Linux from the command line -- The bare essentials, start here

This is the first stop for a new Linux user. This will give you the tools you need to get started navigating the Linux command line.
https://www.linux.com/blog/learn/2018/1/migrating-linux-command-line

Linux from the command line | Learning Linux -- List of useful bash keyboard shortcuts

Linux from the command line | Learning Linux -- List of useful bash keyboard shortcuts
https://www.ostechnix.com/list-useful-bash-keyboard-shortcuts/

Linux from the command line -- Tips and tricks with the vi editor

Linux from the command line -- Tips and tricks with the vi editor
https://opensource.com/article/18/1/top-11-vi-tips-and-tricks

Linux from the command line | Learning Linux -- Understanding the ldd command

Linux from the command line | Learning Linux -- Understanding the ldd command

ldd is a command that some people may never use, but if you do have a need for it, it's indispensable.
https://www.howtoforge.com/linux-ldd-command/

Linux for sysadmins -- Advanced DNSmasq Tips and Tricks

Linux for sysadmins -- Advanced DNSmasq Tips and Tricks

This is really handy for a situation where you don't want or need to run your own DNS server, but you need a little more control than just using a public server.
https://www.linux.com/learn/intro-to-linux/2018/2/advanced-dnsmasq-tips-and-tricks

Linux from the command line -- Having a little fun feigning productivity

Linux from the command line -- Having a little fun feigning productivity

Back in the day a lot of games and goof off software had a "Boss mode", the idea being the if you were playing at work you could hit this hot key and the game would pause and pop up a phony screen that made it look like you were busy working. Most often a spreadsheet page.
If you're a Linux admin, you can also play this game with these tools. Some of them are also good for use when wanting to shoot a fake hacker scene in your indie movie.
https://opensource.com/article/18/2/command-line-tools-productivity

Linux from the command line -- managing network connections with ifconfig & nmcli

Linux from the command line -- managing network connections with ifconfig & nmcli

Once most Linux distros switched to NetworkManager, they left sysadmins hanging by not having a command line interface to control your networks! Fortunately this outrage was eventually rectified with the release of nmcli. Know that like many of these modern Linux tools, the command syntax is convoluted and not easy to learn, remember or use. Hopefully this will help.
ifconfig on the other hand is a classic tool and one you really need to learn because it's standard across all(most?) *NIX like systems. The syntax is fairly standard and easy to use. There's a push to replace it (for some damned unknown reason) with IP which has less useful output and more difficult syntax. Frankly I doubt IP will ever replace ifconfig and I'd learn ifconfig and ignore IP.
http://linuxtechlab.com/managing-network-using-ifconfig-nmcli-commands/

Linux from the command line | Linux Tips & Tricks -- setting up passwordless ssh logins

Linux from the command line | Linux Tips & Tricks -- setting up passwordless ssh logins

Being that ssh is the primary method of communicating between systems, eventually you can get tired of typing your password every time. For convenience and security reasons you can configure ssh to handle the security for you.
Personally I wouldn't recommend that a home network user disable password logins because you can leave yourself stuck locked out of your systems remotely.
In fact for sysadmins I recommend being careful with disabling password logins as well. Take time to think about it and map out your network security zones etc and disable the externally reachable systems first, then work your way in if you think you need more security.
https://www.maketecheasier.com/enable-passwordless-ssh-logins-linux/

Linux from the command line | Linux Tips & Tricks -- correcting typos in bash

Linux from the command line | Linux Tips & Tricks -- correcting typos in bash

While this may seem silly from looking at the examples, it's really useful when the command you made the mistake in was long and complex.
https://www.ostechnix.com/easily-correct-misspelled-bash-commands-linux/

Linux from the command line -- The killall command, with examples

Linux from the command line -- The killall command, with examples

Got browser windows popping up everywhere? System slowing down? Don't panic, don't reboot. Shut them down with killall.
https://www.howtoforge.com/linux-killall-command/

Linux Tips & Tricks -- 8 applications for new Linux users to check out

Linux Tips & Tricks -- 8 applications for new Linux users to check out


https://www.maketecheasier.com/essential-linux-apps/

Linux from the command line -- formatting command output in columns

Linux from the command line -- formatting command output in columns

This is not only a super handy tool, but it's a great example of the *NIX ideology of "Make solid, simple tools that do one thing very well and combine them to build more complex tools"
https://www.tecmint.com/display-command-output-or-file-contents-in-column-format/#

Build your own custom embedded Linux

Build your own custom embedded Linux

With all the IoT devices and Single Board Computers available, and more hitting the market seemingly by the hour, being able to customize them, hack them, and adapt them to your needs may come down to building your own custom Linux system for a specific device and use case.
http://www.linuxjournal.com/content/custom-embedded-linux-distributions

Linux from the command line -- grep by example

Linux from the command line -- grep by example

grep is another key command line tool that every *NIX user needs in their skills tool-box. Like many commands, once you learn what it does, a few examples can be the best way to get a handle on how it works as well as giving you some practical examples to use yourself.


Also see:
https://www.linux.com/learn/glark-better-grep
https://kerneltalks.com/commands/19-grep-command-examples/

Linux from the command line | Linux Tips & Tricks -- save bandwidth and sanity with zsync

Linux from the command line | Linux Tips & Tricks -- save bandwidth and sanity with zsync

zsync can save you a mountain of bandwidth, time and sanity by letting you download only the new parts of a file. For example, if you are downloading successive updates of a beta version of a Linux distribution, you could download a full 4GB ISO file each time, or just once and then maybe just a few megabytes the next time.
OR, maybe you are doing incremental backups of a system over an Internet connection (you are right?).

Note: To install on OpenSUSE use:
zypper in zsync
https://www.ostechnix.com/zsync-file-transfer-utility-download-new-parts-file/

Linux from the command line -- using the md5 command

Linux from the command line -- using the md5 command

md5 is a surprisingly powerful and handy tool. You can use it for security, and to verify a download completed correctly, among other things.
Here are the basics of making it work.
https://www.howtoforge.com/linux-md5sum-command/

Linux Tips & Tricks -- Preventing accidental file deletion with chattr

Linux Tips & Tricks -- Preventing accidental file deletion with chattr

The chattr command is a powerful tool and an essential skill for Linux users. Start here and then go learn more about what it can do.
https://www.ostechnix.com/prevent-files-folders-accidental-deletion-modification-linux/

Linux from the command line - using the seq command

Linux from the command line - using the seq command

The seq command is a perfect example of a command line tool that expresses the *NIX motto of making small, simple tools that do one thing and do it very well and letting you combine multiple of those small tools to build your own, more complex functions as necessary.
https://www.howtoforge.com/linux-seq-command/

Linux Security -- Entropy explained

Linux Security -- Entropy explained

Why you should care. These days everyone is spying on us, from criminals to our own governments and ISP's. To protect ourselves we use things like encrypted passwords, encrypted hard drives, secure VPN's etc. All of these things rely on good encryption and good encryption relies on a good source of good quality random numbers. By good quality we mean numbers that are as close to truly random as possible. The more random, the more secure you are. The problem is that generating truly random numbers is a really difficult task. To the point that governments use things like the decay of radioactive elements, to solar radiation to generate random numbers.
For those that are interested, Linux can use external sources of entropy and there are many sources available, search and find.
http://jhurani.com/linux/2017/11/01/entropy-explained.html

Why you should use named pipes in Linux

Why you should use named pipes in Linux

https://www.networkworld.com/article/3251853/linux/why-use-named-pipes-on-linux.html

Linux from the command line -- tmux for shell power users

Linux from the command line -- tmux for shell power users

I've posted on and praised 'screen' several times in the past for better command line usage, tmux is another great tool for your tool kit and the two actually can work well together. Also, 4k screen users MUST check out tmux.


https://www.2daygeek.com/tmux-a-powerful-terminal-multiplexer-emulator-for-linux/

Linux from the command line -- wget by example

Linux from the command line -- wget by example
http://www.linuxandubuntu.com/home/12-practical-examples-of-wget-command-on-linux

Linux from the command line -- Using the "ln" command

Linux from the command line -- Using the "ln" command

Hard and Soft links are a powerful feature of many operating systems and file-systems. They let you make things appear to be on one place while actually existing in another. The ln command is where it all happens.
https://www.howtoforge.com/linux-ln-command/

Linux Tips & Tricks | Linux from the command line | Linux for sysadmins -- monitoring network bandwidth with iftop

Linux Tips & Tricks | Linux from the command line | Linux for sysadmins -- monitoring network bandwidth with iftop

If you've used Linux for any length of time you've probably come across the 'top' command and it's siblings (htop, atop, etc.) that let you monitor CPU usage. iftop is it's network cousin and like the top family it's a great monitoring and diagnostic tool. See how much bandwidth you're using, what hosts you're using it with, and what tasks are using it.
http://linuxtechlab.com/monitoring-network-bandwidth-iftop-command/