Reboot linux red hat

Common administrative commands in Red Hat Enterprise Linux 5, 6, 7, and 8

A quick update to let you all know that a printable poster of these commands is now available under Attachments.

Does the copyright on the poster allow the .pdf to be distributed? When I transition to 7 I’m going to hang copies in my computer labs, but knowing the students they’re going to ask for copies of the file.

Hi David, unfortunately the copyright does not allow that, but let me see what I can wrangle for you.

Any update, what are the license of theses documents (page and pdf)

Can i hand out copy of them ?

Can i use them for teaching purpose ?

Hi Thomas, at present the license does not allow copying or use for teaching purposes, as this is available only to subscribers. I’ve passed on the request, though, so please stay tuned.

Hi Thomas, just letting you know that we’ve made this publicly available — so, while you still can’t technically copy it for teaching purposes, you can certainly link your students to this page, and they should be able to see it now that a subscription is not required. Hope this helps!

Very helpful for me. Liked the poster, too. Thanks!

Why lot many differences in RHEL7 ?
i like to study it soon

Thanks for the document, very helpful for my team.

Thanks for putting this together. Very useful. Thanks for sharing.

Thanks for this, always great having a quick reference guide!

Any chance of the printable document being in a 2 page format? Unless you have an A2 printer its a little small to read.

One of our graphic designers is working on some more compact versions as I type; I’ll see what we can wrangle.

Many thanks. The exact same format would be perfect, just in 2 pages it then fits perfectly on 2x a3 pages.

Hi Warren, our graphic designer is still working on a split-page version, but I wanted to let you know that the poster has been updated and should now be a little easier to read on a single A3 page. It should also split a little more nicely over two pages if you do need it larger. 🙂 I’ll let you know when a multi-page option is available.

Hi Warren, just letting you know that there’s a multi-page version available now — it was designed for A3, but it’ll still work just fine at A4. 🙂

Lot of Changes in RHEL7 Commands . Need to go through the referance guide and start learn it right now

Thanks for the Great reference sheet

thank you very much!
scared about RHEL7!

helpfull to bootstrap RHEL 7, thanks

Wow, that’s a lot of changes. Anybody ever consider that if you need to create a knowledgebase article and a reference poster to go from one version of RHEL to another that you may be changing too many things too drastically? That’s when stable and dependable products become unreliable.

These are not all changes which Red Hat pushed. Keep in mind: when you use any Linux distribution, you’re benefiting from countless man hours of work contributed by countless members of various communities. We at Red Hat would not be able to make RHEL on our own; it’s made up of hundreds and hundreds of projects which, over time, evolve and change.

I understand that a lot of these changes came from upstream, but surely Red Hat has a lot of clout in the community to nudge the direction of things at least. There are still a few distributions going their own way when the upstream changes are unpopular with their communities, and Red Hat is in a unique position with more resources than many of these. For one example, look to the very short-lived existence of upstart. I’m not sure what happened behind the scenes there, but Red Hat’s implementation was very non-intrusive and wholly backwards compatible with SysV init to the extent that you could run a RHEL server and not even realize that upstart was there. Now it’s been tossed to the side as quickly as it appeared.

From what I’ve seen/heard of 8, I’m questioning if Red Hat has lost the script. It’s been my preferred enterprise distro for years because it did what it does very well with rock solid dependability and a core focus. Maybe its time to split into a few products and introduce a RHEL Classic with all the flavour your remember from way back when.

I hear you John. While I wasn’t in a position to make any decisions regarding RHEL7, I have been using Fedora on my personal systems for years and years so none of these changes came as a shock to me; however, I have many colleagues (sysadmins or not) who have expressed similar feelings about RHEL7.

As a sysadmin, support tech, and teacher-trainer, I’m always focused on learning new things — grow or die, IMHO — but I know many people just want to get on with their jobs and their lives. That said, in dealing with my colleagues, so far, not one of them has held on to their scepticism about a particular RHEL7 component (e.g., systemd, firewalld, grub2, new-anaconda, targetcli, NetworkManager) once they’ve actually taken the time to learn about the how/what/why of it.

Of course the natural response to my statement might be «but we don’t want/have the time!» . To which I can only say: RHEL6 isn’t going anywhere.

PS regarding upstart in RHEL6: I can see why you’d say that Red Hat’s implementation was non-intrusive — after all we kept the whole SysV init rc structure completely intact! Keep in mind however that in doing so we didn’t take advantage of any of the job-control or event-based parallelization features upstart had to offer. It was great that most people didn’t have to learn anything new, but most people also didn’t notice any improvement over init from RHEL5.

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How To Restart CentOS, Fedora, RedHat?

CentOS, Fedora and RedHat are Linux distributions of the same family. These distributions provides different ways and command in order to restart. In this tutorial we will look different ways to restart CentOS, Fedora and RedHat and their affect to the system.

Restart with Shutdown Command

shutdown command is the most common way to stop or restart the system. Without providing an option shutdown will shutdown the system but will not restart. We will provide -r option in order to restart the system like below.

Restart with Shutdown Command At Specified Time

By default shutdown operation starts immediately. But we have the option to reboot at specified time in the future. We generally use minutes after to reboot. In this example we will restart the system after 5 minutes by providing +5 option.

Restart with Reboot Command

Reboot is actually not a command. reboot is a script which is alias for shutdown -r . So their affect will be the same. We can use reboot command like below. reboot also does some hard disk maintenance like sync etc.

Restart with Halt Command

We can use halt command with —reboot option. halt command provides some log to the utmp . Most init scripts call halt for logging options. We can restart system like below with halt command.

Restart with Init Level

Linux uses init levels in order to specify current working mode. Level 6 is used to specify the reboot state. We can use init command in order to change Level 6 which will reboot the system. By using init related init files will be executed and invoked.

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How to boot, shut down, and suspend your system from the Linux command line

Learn how to schedule timed shutdowns and reboots with systemd and to hibernate your system with systemctl.

Let’s face it: The most fundamental thing we do with computers is turn them on and off. Everything else happens between those two particular events. And sometimes, restarting the system is a key component of troubleshooting or completing installation processes.

Training & certification

Typically, you need root privileges to shut down or reboot the system. Ensure your account is configured in /etc/sudoers for this authority. Remember, it’s generally a bad idea to log on directly as root.

Boot the system

Starting the system is as simple as pressing the power button. What happens from there varies a bit depending on your hardware, but in general, the process looks like this:

1. The firmware (BIOS or UEFI) finds the boot media.
2. The boot loader starts, and the Master Boot Record (MBR) or GUID Partition Table (GPT) loads.
3. The operating system selection menu appears.
4. The boot loader stage 2 starts and loads the selected kernel.
5. The kernel and drivers load and mount the root filesystem.
6. systemd launches as PID 1.
7. The default.target file loads.
8. The user is prompted to authenticate.

The system launches to the default.target (providing either a command-line interface or graphical environment). Changing these targets is outside the scope of this article but is something I cover in How to switch between the CLI and GUI on a Linux server.

Shut down the system

When Red Hat Enterprise Linux (RHEL) adopted systemd with RHEL 7, what happened to the venerable Linux shutdown command? It remains—but now it maps to systemd’s shutdown functions.

The shutdown command features two options: —halt and —poweroff . The —halt option stops the operating system while the —poweroff option turns off the system.

One of the main benefits of the shutdown command is the ability to define a shutdown delay to give users time to save their work and log off the system. Schedule a time that suits your needs by using the format hh:mm (24-hour time designations).

For example, to halt the system at 10pm, type:

It’s more likely that you’ll want to halt the operating system a few minutes into the future. In that case, specify the number of minutes from now to begin the shutdown process.

For example, to halt the system after a five-minute delay, type:

You can append a message to all users by entering it after the time specification, like this:

$ sudo shutdown --halt +5 “Attention. The system is going down in five minutes.”

Cancel a timed shutdown by using the -c option:

You can also use the systemctl command to shut down the system. For example, type systemctl halt or systemctl poweroff to achieve similar results to the shutdown command. The main disadvantage of using systemctl is losing the ability to schedule or cancel the shutdown process.

Reboot the system

When someone approaches you for help with their computer, I suspect one of your first responses is, «Did you reboot it?» Restarting a computer helps with various problems and may even be necessary to finalize some configurations. However, restarting is considered downtime on a server and should be avoided if possible. Try to use systemctl restart to restart services rather than reboot the whole system.

However, sometimes a restart is inevitable. The option for restarting the system immediately with the shutdown command is -r , so it looks like this:

You can still specify a delayed time using the hh:mm format explained above.

You can also use systemctl to reboot the device by typing:

Again, the disadvantage with systemctl is the inability to delay the process.

Suspend the system

Great Linux resources

There are a couple of ways to place the system in a reduced or no-power mode. The first is suspend and the second is hibernate.

When you suspend the system:

• Contents of memory are moved to the swap location.
• The boot loader is configured to boot directly to the current kernel.
• The system shuts down (no-power mode).
• Upon power up, the system reloads itself from swap.

When you hibernate the system:

• Applications are stopped.
• System state is moved to RAM.
• The system remains powered on in a low-power state.

You can also suspend and hibernate the system by using the systemctl command. The commands are exactly what you’d expect:

$ sudo systemctl suspend $ sudo systemctl hibernate $ sudo systemctl hybrid-sleep

The systemctl hybrid-sleep command both suspends and hibernates the system.

Use the GUI

Depending on the graphical user interface (GUI) environment you have installed, you can initiate a reboot or shutdown from a menu. Many people rely on a graphical desktop like GNOME, so this is certainly a viable option.

[ Because sudo is something you don’t configure often, it can be hard to remember its nuances. Download the Linux sudo cheat sheet. ]

Wrap up

The familiar shutdown command now maps to systemd and executes timed shutdowns and reboots. You can use systemctl if you wish, but being able to schedule the shutdown is helpful. In addition, systemctl also offers suspend and hibernate options. Try to avoid bringing down the system when possible, but sometimes it’s necessary.

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