Category: Tips

Show A Specific Networking Interface

Today, I’m just going to write about a simple task, how to show a specific networking interface. This seems like a good short article.  It won’t be too complicated and it’s suitable for a beginner. Read on, if you are interested in learning how to get the information for just a specific networking interface.

It’s also suitable for most people, as most people only need information from a single, specific networking interface. Most folks reading this site are home users of Linux and it’s quite likely that they’re only connecting over one network interface, be it ethernet or wifi. Frequently, you only need to show a specific networking interface when gathering information from the terminal.

If you’re still using ‘ifconfig’ you can close this tab immediately. The tool is deprecated and we’ll just be using the ‘ip’ command. Odds are good that your distro has already moved away and is using the ip command. If your distro hasn’t done so, it should be noted that the process of deprecating ‘net-tools’ (from which you get ifconfig) started in like 2001. You may still have the legacy tool, but we won’t be covering it.

Anyhow…

That’s a long intro for something this short…

Show A Specific Networking Interface:

This is yet another article that requires an open terminal. So, crack open your favorite terminal. If you don’t know how to open the terminal, you can do so with your keyboard – just press CTRL + ALT + T and your default terminal should open.

With your terminal open, you can run the following command:

You can even run:

Or, you can get that information for a specific networking interface. To do so, we just use the first command, like so:

For example, if your NIC is called ‘eth0’, the command would look like this:

The output from that command will be just the information about that specific networking interface. You won’t have the clutter of the first two commands listed and it will only show the device you specify. If you’ve only got one network interface in use, you can just store the final command in your memory for when you need to check some of your networking information.

Closure:

See? I told you that it’d be quick and easy. Not all of these articles need to be long and complicated. Besides, my 2-year anniversary is coming up, meaning a short and simple article is a good thing. I don’t want to burn out or anything, not at this stage of the game.

Thanks for reading! If you want to help, or if the site has helped you, you can donate, register to help, write an article, or buy inexpensive hosting to start your site. If you scroll down, you can sign up for the newsletter, vote for the article, and comment.

Another Way To Find A Website’s IP Address

Today’s article will just be a fun one, where we cover yet another way to find a website’s IP address. It’s mostly for fun but it’ll also introduce you to another tool for your terminal-toolbox. After all, there’s almost always more than one way to do things in Linux, including finding a website’s IP address.

So, today we’ll be using a tool I don’t think I’ve covered before. While we have done the website IP address thing before, I don’t see the ‘nslookup’ tool anywhere in the site’s history. We might as well, as I could use a quick and easy article today, as I’ve been busy making a delicious ham.

Odds are good that you have nslookup installed by default. If you don’t, it’ll be easy enough to install with your package manager. If you check the man page, you’ll find the tool describes itself as:

nslookup – query Internet name servers interactively

And, yeah, that’s what we’ll do with nslookup. We will use it to do what it’s designed to do. We do that often around here and, of course, we’ll be doing all this in the terminal. I’m sure there’s some GUI tool you could use, but every Linux distro that I know of comes with a terminal. It just makes good sense for most articles!

Well, that’s enough blathering about what you’re going to read…

Find A Website’s IP Address:

As the intro mentioned, we’ll be doing this in the terminal. So… Open a terminal of your choosing. If you don’t know how to open the terminal, you can do so with your keyboard – just press CTRL + ALT + T.

With your terminal now open, the syntax is simple:

You’ll often get more than one IP address in the answer, but that’s because sites will often respond on more than one IP address. For example (and considering that I’m behind a CDN), this site would look like this:

it's easy to find a website's IP address
See? It’ll answer on an IPv4 or an IPv6 address at this time. Pretty easy, huh?

Go ahead and try using nslookup to find the IP addresses of your favorite sites. There’s no harm in doing so and it can be a useful bit of information – though usually, that’s more useful for the site’s admin. Still, it can be a handy bit of information.

Closure:

There! See? Another quick and easy article. This time, we’ve shown another way to find a website’s IP address. It’s not complicated and the output is easy enough to process. Enjoy the tool and have fun with it.

Thanks for reading! If you want to help, or if the site has helped you, you can donate, register to help, write an article, or buy inexpensive hosting to start your site. If you scroll down, you can sign up for the newsletter, vote for the article, and comment.

How To: Clear Swap

Today’s article is just going to be a quick and easy article, where we learn how to clear swap. I figured I’d do this article while swap was still fresh in my memory so that I’d not forget to write it down the road. If you use swap and want to learn how to clear swap, read on!

Again, this article is only useful for those that use a swap. There are different opinions about using swap and this article is for those who do. I just wrote an article about how to monitor swap, so we might as well learn to clear it.

What do I mean by clearing swap? I mean emptying it. I mean removing all the data held in swap, allowing for data to be written to swap again. It’s not something I worry about, but I know folks have asked about it in the past. I might just as well cover it, though it really won’t take much time.

Clear Swap:

This article requires an open terminal, like many other articles on this site. If you don’t know how to open the terminal, you can do so with your keyboard – just press CTRL + ALT + T and your default terminal should open.

With your terminal now open, you can clear swap with the following command, by turning swap off:

You then turn swap back on with:

Tada! You’re all done. If you want, you can do it all with just a one-liner:

That’s really all there is to it. It’s not terribly complicated and it’s something you might as well know if you’re going to use swap and are concerned with monitoring and clearing it.

Closure:

There you have it. I told you that it’d be short and easy. You now know how to clear swap, should you actually want to do so. You might as well know how. It’s bound to come in handy for someone.

Thanks for reading! If you want to help, or if the site has helped you, you can donate, register to help, write an article, or buy inexpensive hosting to start your own site. If you scroll down, you can sign up for the newsletter, vote for the article, and comment.

A Couple Of Ways To Monitor Swap Usage

Today’s article will be nice and easy, as we cover just a couple of ways to monitor swap usage. There are several ways to monitor swap usage, so we’ll just cover a couple of them. One of ’em is bound to work.

So, this only applies to those people who use swap. If you use the search feature, you’ll see that I’ve addressed this before and that I tend to use swap – because it’s more than just a place the kernel sticks stuff when you’ve run out of RAM.

swap is still used with plenty of RAM
See? The system happily uses swap with plenty of free rams.

As you can see, on a system with plenty of RAM – and plenty of free RAM – the system still uses swap. I figure that the kernel is smarter than I am. You do you, but I will continue using swap.

But, enough about that. If you don’t use swap, just accept that this article isn’t meant for you and move along. Tomorrow’s article might just have something useful for you. You never know!

So then, I will assume readers know enough about what swap is and will have made their own choices. This article is for those who want to monitor swap usage.

Let’s Monitor Swap Usage:

You guessed it. You’re going to need an open terminal. So, open your favorite terminal emulator. If you don’t know how to open the terminal, you can do so with your keyboard – just press CTRL + ALT + T and your default terminal should open.

With your terminal now open, you can try the following command:

(You can just use ‘free‘ but the -m flag makes it easier to read. You can also use ‘free -h‘ if you prefer that output.)

That command should be fairly universal. You can also use the following command if you’d prefer. It’s just:

That command is pretty handy and pretty much is the same as you’d get if you just run’cat /proc/swaps‘ which is, I suppose, yet another way for you to monitor swap usage. Think of it as a bonus way to check swap usage. After all, you can’t have too many ways and one of ’em is bound to stick with you if you use it often enough.

Closure:

And there you have it. You have another article. This time, we’ve discussed how to monitor swap usage (in the terminal, of course). It’s a handy tool for those who do use swap (be it partition or swapfile). If you don’t use swap, you probably won’t get much use from this article. Maybe tomorrow will be more interesting for you?

Thanks for reading! If you want to help, or if the site has helped you, you can donate, register to help, write an article, or buy inexpensive hosting to start your site. If you scroll down, you can sign up for the newsletter, vote for the article, and comment.

Let’s Play With Touch And Time

Today’s article is just a fun article where we get the chance to play with touch and time. This article won’t necessarily be something you rely on daily, but it should at least be informative. That and there’s surely a subset of users who use these commands. There’s bound to be! Otherwise, why would they make touch flags for adjusting the time?!?

We’ve used the ‘touch’ command before.

Some Useful Ways To Use The Touch Command In Linux

I’m pretty sure we’ve also used the touch command in at least another article. There are a lot of search results for the word and it’s not important enough to go looking. The key point is that touch is a command you use in the terminal and it describes itself as:

touch – change file timestamps

See, we (and perhaps most other sites) have used the touch command to *make* files, but it’s useful (and intended for) changing file timestamps. Like oh so many commands, there are all sorts of ways to use it and so many folks do things in their own way. The great thing about Linux is that we have so many choices.

This is why I figure I’ll cover touch and time in this article. It’s just a few commands that we’ll be using, so it’s not all that advanced. A beginner probably won’t need to know this sort of information, but it’s information worth sharing.

Playing With Touch And Time:

As we use touch in the terminal, you’re going to need to have an open terminal to play with touch and time. If you don’t know how to open a terminal, press CTRL + ALT + T and your default terminal should open.

With your terminal now open, let’s start by creating a file:

That command will create a file with a created timestamp from the time you ran the command. If you want, you can change the access time, that is the time stored with the file that says when it was last accessed. Run the following command with the -a flag:

That’ll change the ‘foo file’s access time to the time when you ran the command. All well and good? Alright… Let’s remove that file with:

Now, we’re going to create the foo file again, but we’re going to give it a specific timestamp. The format you want is:

Or, something like this:

That will give the file a timestamp from March 3rd at one minute and one second past midnight. Note the period denoting seconds as that’s the only modifier you need for this command.

NOTE: If you use a different time format, that command might be different for you. I don’t think it is, but I’m not set up to test that. If it does matter, please let us know in a comment, thanks!

Finally, let’s say you have a file named ‘bar’ and you want ‘foo’ to have the same timestamp that bar has. You can do that with the touch command. It’s relatively easy to do with the -r flag:

That command will give foo the same timestamp that bar has, should you be inclined to do so. It’s pretty easy to use the touch command to change a timestamp on files, which is why you might not want to rely too much on timestamps. They can be useful, but they are not immutable. 

You can run the command above to delete the foo file when you’re done playing around with the touch command:

Closure:

There you go, another article. This time, we’ve had an article about using touch and time, which is kinda why the touch command exists in the first place. It’s far more useful than just creating files. Be sure to run man touch (no inappropriate jokes) in the terminal to learn more about the touch command. There are other touch commands that you may find yourself interested in, I’ve just covered a few of them.

Thanks for reading! If you want to help, or if the site has helped you, you can donate, register to help, write an article, or buy inexpensive hosting to start your site. If you scroll down, you can sign up for the newsletter, vote for the article, and comment.

Linux Tips
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.