Category: Tips

How To: Show Hidden Files And Folders

Today, you’ll read an article that tells you how to show hidden files and folders (in Linux, of course). This is something everyone should know. This is a basic skill that you’re almost certain to need if you make the decision to use Linux.

Fortunately, it’s pretty easy to show hidden files and folders. You’ll see…

First, I should probably explain what hidden files and folders are. They’re files and folders that start with a period. So .foo.txt is a hidden file and .bar could be a hidden directory. One should remember that Linux is, by design, a multi-user system. With that in mind, having hidden files makes sense – if you don’t want those files to be accidentally (or maliciously) edited.

Any files or folders that begins with a period will be a hidden file. If you’re new to Linux, you might want to leave them hidden until you’re a bit more comfortable working with system files. Or not… It’s your system, you do what you want with it.

In a GUI file manager, you can usually figure out how to show hidden files and folders pretty easily. Sadly, it’s not universal in a GUI. Look in the right click menu, under the “View” option, or in the application’s preferences. It’s also often ALT + H and I want to say I’ve even seen it be ALT + F4. Look around, you’ll find it.

This article is more about showing those hidden files and folders in the terminal. It’s a really easy command and won’t take too long to explain it to you. So, enough preamble, let’s begin.

Show Hidden Files And Folders:

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.

We’ll stay right in the default directory, your home directory. If you’re not currently in your home folder,  you can get there with:

Your home folder should have all sorts of hidden files and folders. First, let’s see your home directory without showing the hidden files and folders:

Unless you’re in the habit of storing files in your home directory, you should have a fairly tidy list of folders and files that you’re likely already familiar with. 

Now, let’s try again – this time showing hidden files and folders:

Or, you can get a more easy to read output with this command (and you get more information with it):

If you want to see it in action, you can try this command:

Now, if you use the ls command you won’t see that file. If you use the ls -a command you’ll see the hidden file that you created called .foo.txt. This of works with directories, as they too can be hidden.

Yup, that’s it. That’s today’s article. See? I told you it was easy.

Closure:

Indeed, it is an easy article – and one most of my readers will already know. This one is aimed squarely at the new user who has yet to learn how to show hidden files and folders. It’s a pretty important skill to learn, and it’s also important to know which ones you probably shouldn’t edit. So, judicious use is important.

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How To: Free Some Disk Space By Deleting Old Logs

In today’s article, we’re going to free up some of your disk space by deleting old logs. It’s a relatively safe and easy thing to do, and can free some space up if you’re running low. Unless there’s a problem, you really don’t need a bunch of old logs kicking around and taking up space.

There are other reasons for deleting old logs, such as keeping things tidy or even ensuring old activities aren’t easily discovered by browsing old log files. You may have done some debugging and now want to start with a new slate, so there’s another reason to delete logs. 

Who knows what motivations you’ll have, but today we’ll be covering how to do it. The tool we’ll be using for log cleaning is ‘journalctl’, which is used for (according to the man page):

journalctl – Query the systemd journal

While ‘journalctl’ is a pretty nifty tool, we’re only going to scratch the surface. This article is only about deleting old logs and ‘journalctl’ is just the tool we’ll be using. If you want an article about all the features of ‘journalctl’, this is not that article. See? I’m saving at least a few people some time!

Anyhow, this article obviously requires a distro that uses ‘systemd’. If you don’t have ‘systemd’, you probably don’t have ‘journalctl’ and you’ll have to find another way to delete your logs. As most mainstream distros are using ‘systemd’, there’s a pretty good chance that you have ‘journalctl’ available.

So, with all that preamble gibberish out of the way, let’s go about …

Deleting Old Logs:

Like oh so many articles here, this one requires an open terminal. Why? Because of course it does. 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.

Now, with your terminal open, let’s have a look and see how much space your logs are taking up. You can do that with this command:

Now that you’ve seen how much space your logs are taking up, there are a couple of commands you can use for deleting old logs. If you want to go by space, you can use this command:

You can edit the ‘100m’ to whatever suits your needs. You can also use ‘g’ for gigabytes if you’d like to keep using that much log space.

If you want, you can also delete your old logs by the day. Let’s say you want to retain the last 3 days of logs. Well, that command would be:

I suspect you can figure out that the ‘d’ stands for ‘day’ and the 3 is how many days. You can, of course, change that to any number of days you wish. If you want, you can even use ‘w’ for weeks. Though, if you’re deleting log files to clear up disk space, you’re probably going to want to trim the logs even more than that.

Anyhow, when you’re done running one of the cleaning commands from above, you can verify that the space has been cleaned by running the very first command listed. That will do exactly what it did the first time you ran it – it’ll tell you how much space your logs are taking up. If they’re still not small enough for your liking, feel free to edit and run one of the above commands a second time.

Closure:

Well, there you have it… You have another article! This time I tell you how to go about cleaning old logs from your system. It’s a handy skill to have, though most folks probably have ample disk space – except those running on stuff like Chromebooks or the likes. If you’ve gotta live within 16 GB, you’re going to want to keep your logging to a minimum. Also, I still haven’t skipped a day from writing articles. It seems likely that I’ll do so eventually!

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How To: Add A User To A Group

Today’s article is going to teach you how to add a user to a group. It’s not particularly difficult, but it’s something everyone should know. If you don’t know how to add a user to a group, this article is meant for you.

This article is going to make a few assumptions. The first is that you’re familiar with cat /etc/passwd which will tell you what groups a user belongs to. It also assumes that you’re familiar with cat /etc/group – where you can find supplementary information.

Furthermore, you should also be aware of the groups command, which is a handy command, probably worthy of its own article, that lets you know what groups you already belong to. So, there’s a bit you’re expected to know already, or at least be familiar with conceptually, but trust me when I say this is a very simple article and very straightforward.

Anyhow, if you’ve looked at those previous commands, you’ll see there are a lot of groups. Your user may or may not be a member of those groups, as the groups command will let you know. For myriad reasons, you may wish to add yourself or another user to different groups. Well, that’s what this article is actually about. It’s about showing you how to …

Add A User To A Group:

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.

The command we’ll be using for this exercise is ‘usermod‘. You can get a head start by using ‘man usermod‘ but we really won’t be needing most of that information. In reality, we only care about a couple of the flags. Still, usermod is a pretty expansive command, with many options. Still, it defines itself simply as:

usermod – modify a user account

See? Pretty straightforward still. The command we actually want is:

The -a means append (add) the user. The -G means groups – so the -a -G means add a user to a group. You can verify the command worked (though, well, you really don’t need to – ’cause, assuming  you did it properly it’ll work) with the following:

See? That’s it. You’ve learned how to add a user to a group – in under 500 words!

Closure:

Yup, it’s a nice and easy article for a skill you may need as you work with advanced group permissions. If you want to refine the permissions in your system, the sky’s the limit and it’s easy enough to add a user to a group if you need to. So, there’s another tool in your toolbox.

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Find Your Linux System’s Timezone

This article, telling you how to find your system’s timezone, is more aimed at server users than desktop users. Desktop users probably know this already.

This command is most useful when you’re dealing with servers across the globe. You may want to schedule things (for one small example) to run at local times and knowing the local time will help with that. Knowing the timezone is pretty important, and the timezone itself is important.

The timezone dictates things like when your clocks change to adjust for Daylight Savings Time. While that may not seem like a big deal, having the proper date and time is a big deal. So, this article will tell you a couple of quick and easy ways to find your Linux system’s timezone.

Find Your Linux System’s Timezone:

This is going to need an open terminal. You probably could have guessed that. You can open a terminal with your keyboard – just press CTRL + ALT + T and your default terminal should open.

With your terminal open, you can try one of the following commands (I prefer the first):

The second option is easier to remember, but you don’t get the full name of your timezone. It may require a bit more thinking, just to be sure. Try:

And the timezone will be at the end of that string of characters. If you’re still confused, you can type the abbreviation into your favorite search engine and they’ll get you sorted out.

Thee is a third way, but keeping that way crammed into memory isn’t as easy as the date command. It’s just:

Of course, you can just use ​’timedatectl’ without grep. That’s a viable option, it just spits out more information. So, if you were to remember just one of the commands, the third one is probably the best.

Those are three ways I know of to find the timezone within the Linux terminal. It may show up in the GUI. If you want to add it to your system’s time display, you add %Z to the string (ISO 8601 standardizes this) and it’d look something like this when you changed it and the change took place:

Using the #Z to show the timezone in the system clock.
Tada! That’d be how you’d do that!

So, you can display the timezone in the GUI if you really needed to. But, this article is mainly for those who admin servers across the globe and need to know the timezone the system is in.

Closure:

Woohoo! Another article done and ready to publish. However, I’m going to leave this one unscheduled (scheduled way in the future) so that I have an ’emergency’ article, an article that can be used when Mother Nature has taken out my ‘net or motivation just isn’t there.

Either way, this article covered how to find your timezone in Linux. It’s information you may want, and information you may want to check before rolling out changes. The data is in the system, we just need to pry it out.

Find Out Which Shell You’re Using

Today’s article is going to teach you how to find out which shell you’re using. Knowing which shell you’re using is important if you’re using an unfamiliar system. Most of the time, it’s something you’d already know, but once in a while you might need to find out which shell you’re using.

As you’re visiting this site, it’s fairly safe to assume you’re using Linux (or at least interested in Linux). In that case, you’re quite likely using Bash. Bash is the most common, from my observations.

If you’re curious, Bash is a replacement for Bourne Shell – and is ‘Bourne Again SHell’. It has existed, thanks to the Brian Fox and the GNU Project, since the late eighties. It’s pretty ubiquitous, pretty stable, and pretty feature complete.

While Bash is the most common, it’s certainly not alone in the field of shell options. There are other shells, from ZSH to Fish, or from Dash to Nushell. In some distros, you might find one of them installed by default, but it’s usually going to be Bash.

So, odds are pretty good that you will already know if you’re using something other than Bash. After all, you’d likely have been the person who installed the alternative. Still, there are a couple of commands you can use when you want to figure out which shell you’re using, for when you do need to know.

Find Out Which Shell You’re Using:

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.

On the off-chance that you don’t know what a shell is, Wikipedia describes the shell as:

A Unix shell is a command-line interpreter or shell that provides a command line user interface for Unix-like operating systems. The shell is both an interactive command language and a scripting language, and is used by the operating system to control the execution of the system using shell scripts.

And now, with your terminal emulator open, let’s go about finding out which shell you’re using. 

The first command you can try would be:

You can also use the echo command in a different way. It’s even a bit more clear with this command:

You can also use ‘ps’ which takes snapshots of current processes:

There are certainly other ways to find out which shell you’re using, but those are a few ways that are easy enough. If you have other ways, please feel free to leave them as a comment.

Oh, and here’s a bonus… If you want to see which shells are installed on your system, you can use the following command:

The output of this would look similar to this:

list of installed shells
This is the defaults from Lubuntu 20.04 LTS. Your output may vary, of course.

As I said, that’ll let you know which shells you have installed. In a future article, we might discuss how to change your default shell – but that’s something I seldom bother with these days. Bash works and works well.

Closure:

Yup… There it is! Another article. Now that the year is up, I’m not sure what to look forward to as a goal. I highly doubt I’ll make it a full two years, but it could happen. We shall see…

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.

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