Command Line Archives • Page 26 of 77 • Linux Tips

Let’s Password Protect A File

Today’s article is a fun one, where we’ll learn how to password protect a file using something called GPG. It’s not complicated. You can learn how to password protect a file in just a few minutes. You can then send these files out and other people can decrypt them – assuming you’ve shared the password with them.

We all have secrets. They’re not all digital, but they could be. We may also want to be able to share files that have private information in them, meaning you only want people with the password to open it. Though, I suppose, brute force is always an option – but you can at least make it difficult by using a complex password, preferably one that you didn’t generate yourself.

So, what is GPG? GPG stands for “GNU Privacy Guard”. It’s fairly standard and used quite a bit. There are other applications, like PGP, but I think all of you folks that use a ‘full’ distro will have GPG installed by default. It’s one of those tools that you might not use all that often, but it seems to be included by default in a lot of places. I suspect that’s because other things rely on GPG, but I’m way too ~~lazy~~ inept to look that up.

By the way, the GPG man page describes it as:

gpg – OpenPGP encryption and signing tool

That GPG is what we’re going to be using for this exercise. Trust me, it’s easier than you might think.

Password Protect A File:

Do I have to mention it? Of course I do! It’s time for your favorite thing, an open terminal ready for your commands. You can open your default terminal by pressing CTRL + ALT + T.

With your terminal now open, the command to password protect a file would be:

gpg -c /path/to/file

1	gpg -c /path/to/file

The -c flag stands for encryption. It should then ask you for a password, that you’ll need to enter twice, and then it will make an encrypted copy of the file with a .gpg extension. The original file will still exist, so this isn’t encrypting that original file. It’s making an encrypted copy and you’ll want to safely delete the original file if that’s your intention.

Now, to open the new <file_name>.gpg file, you’ll need to use the following command:

gpg <file_name>.gpg

1	gpg <file_name>.gpg

Now, when I went to open that with the same computer and the same session it didn’t ask for a password. I shipped it to another computer and it did just that. I do not know why.

When you successfully open the password protected file, it will ask you if you want to overwrite the original. This shouldn’t happen when you ship it to someone else unless they happen to already have a file with that specific name. It also will let you say don’t want to overwrite the file and let you pick a new file name for the unencrypted content.

Closure:

You can actually do this with a folder if you’d prefer. It’s just specifying a folder instead of a file. The process is exactly the same. So, like I said in the start, it’s a really easy task to password protect a file. The terminal is useful for all sorts of stuff.

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.

How To: Find Out Which Window Manager You’re Using

Today’s article shouldn’t be all that long or difficult, as we simply go over how to find out which window manager you’re using. In the Linux world, this is often abbreviated as “WM” but we’ll avoid using the abbreviation ’cause of search engines. Yeah, search engines have a lot to do with how this (and every other) site is configured – including deciding how I write articles.

Yay! We need to appeal to you AND the algorithms. We’re all slaves to the machine!

So, what is a window manager? We can cheat and cite the Arch Wiki (a brilliant source for all things Linux). They define window managers as:

A window manager (WM) is system software that controls the placement and appearance of windows within a windowing system in a graphical user interface (GUI). It can be part of a desktop environment (DE) or be used standalone.

Further, there are the following clues:

Window managers are X clients that control the appearance and behaviour of the frames (“windows”) where the various graphical applications are drawn. They determine the border, title bar, size, and ability to resize windows, and often provide other functionality such as reserved areas for sticking dockapps like Window Maker, or the ability to tab windows like Fluxbox. Some window managers are even bundled with simple utilities like menus to start programs or to configure the window manager itself.

Now, in modern times, most of you will be using the window manager that came with your distro and you’ll just leave it as the default. This article is for that person – the person who didn’t install their window manager and doesn’t know which window manager they’re using.

Which Display Manager Are You Using:

You guessed it! You’re going to need to use a terminal for this. Oh, there are surely GUI ways to do this, but I know you have a terminal. You can just press CTRL + ALT + T to open your default terminal.

With your terminal, you can run the following command:

wmctrl -m

wmctrl -m

If that command doesn’t spit out the information you’re after, you may need to install it. Your trusty default terminal should happily tell you how to install wmctrl, but it’d be (in Debian/Ubuntu/Mint/etc) something like this:

sudo apt install wmctrl

1	sudo apt install wmctrl

Of course, if you have Neofetch installed, you can just run Neofetch. Like ‘wmctrl’, you might need to install it. You might as well install it, though you could just as easily use Screenfetch. You get to pick which one you want to use, but it’ll be listed under the aforementioned abbreviation of “WM”. See? Foreshadowing! I can’t believe you read this nonsense.

So, there are a few options to find out which window manager you’re using. You can pick which you like most, but either of the *fetch applications will give you more system information. Do what you must…

Closure:

I planned on another article, but this one seemed like a more interesting article to write today. As it seemed more interesting to share how to find which window manager you’re using, I decided to go with that one.

These “easier” articles take about the same amount of time to write. The subject is often decided by what I feel is the most interesting. You can always start your own site and write along with me. There’s room for all of us!

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: Have Infinite Bash History

Today we’re going to have a good time because we’re learning how you can have infinite Bash history. There’s a bit more to it and not all of you will want an infinite Bash history. But, for those that do, we’re going to accomplish that right here in this article!

First, I’m assuming you’re using Bash as your shell. The odds are really good that you’d know if you’re not using Bash, as Bash is pretty much the default. Bash is the interactive shell you’re using, known as Bourne Again Shell. If you don’t know what shell you’re using, I covered that in an article about determining the shell you’re using.

Side Note: I sometimes write articles that are meant to preface another article, but then I forget and don’t write the additional article. I suppose that helps keep things interesting…

So, as you know, when you type a command into the terminal that command is stored in a file typically called ~/.bash_history – a hidden file in your home directory. Well, there’s a limit to how much history that file will retain and this is Linux – meaning that, of course, you can change that value. Today, we’ll be changing that value – making it ‘infinite’.

No, of course, it’s not really infinite. There’s a finite amount of disk space you have. This being a plain text file, it takes up very little space. While it’s not technically infinite you can store a whole lot of entries in your Bash history. We’ll set it to infinite, but I’ll show you how to set it to any value you want.

Ready?

Infinite Bash History:

As you can see, this is a Bash thing. That’s a good sign that you’ll need an open terminal. You can press CTRL + ALT + T and your default terminal should open. See? We’re already making progress!

With your terminal open, we’re going to edit another hidden file. The name of this file is .bashrc and it’s a file that stores things like terminal settings.

The tool we’ll be using is ‘nano‘. Click that link to learn about Nano, including how to install Nano should Nano not come preinstalled in your chosen distro. As you may know, Nano is one of my favorite text editors. We use Nano a lot around here.

Start with opening the ~/.bashrc file with nano, like so:

nano ~/.bashrc

1	nano ~/.bashrc

Scroll to the bottom and add the following lines:

#infinite history hack
HISTFILESIZE=-1

1 2	#infinite history hack HISTFILESIZE=-1

Any negative value, in this case, -1, will result in an infinite history. However, you can make that value any number you want. When you’re done adding those lines, you have to save the file. Remember, to save a file in Nano, you just press CTRL + X, then Y, and then ENTER.

You could make the value 5000, for example. That’d simply look like this:

#infinite history hack
HISTFILESIZE=5000

1 2	#infinite history hack HISTFILESIZE=5000

The sky is the limit. You can make that value any number you want, but all negative values will be treated the same. If the value is negative, it means you’ve got an infinite Bash history. Don’t forget to save any changes with Nano, as instructed above.

Now, you could reboot or log out to make the new settings take effect, or you can simply tell your system to reload the file to make the changes take immediate effect. That’s an easy command, simply use:

source ~/.bashrc

1	source ~/.bashrc

As you can see, infinite isn’t infinite (nothing is in the real world, according to current observations) and you don’t have to choose the infinite setting. You can pick whatever numbers you fancy and the process is the same.

Closure:

There you go, you now know how to set up your system to have an infinite Bash history. Well, an infinite ~/.bash_history if you prefer. With that setting engaged, you’re limited only by your creativity, fanaticism, and disk space. Go nuts with it! They make bigger disks! (Also, it takes up very little space.)

Let’s Make A Directory Tree

Today we’re going to install a nifty application and then we’re going to make ourselves a directory tree. We’ll learn a couple of other things along the way, as we often do. Linux is great like that, and so we’ll have some fun along the way – including generating an entirely pointless text file that takes up too much space and takes too much time! That sounds fun to me!

So, what is a directory tree? Well, you start in one directory and then make a “tree” of all the directories below it. The directory you start in will be the top of the tree, and the directories below will be the branches. In its simplest form, it might look a little like this:

using the tree command to make a directory tree — As you can see, that’s part of the tree – with various directories and sub-directories.

You can’t see the parent directory, but there is one. That’s just a piece of the tree, which should be enough to explain this tree concept.

The tool we’ll be using is known as ‘tree’, of course. The man page describes it as being:

tree – list contents of directories in a tree-like format.

You may not have ‘tree’ installed and you will need to install it. It should probably be a default tool, but it is not. Use your package manager, search for ‘tree’, and install it. In Ubuntu/Debian/Derivatives, you can try:

sudo apt install tree

1	sudo apt install tree

That should get you started and, with tree now installed, we can…

Make A Directory Tree:

If you had your terminal open to install ‘tree’, you might as well leave it open. You’ll need it for the rest of this article. If your terminal is not open, you’ll need to open it. Just press CTRL + ALT + T. Tada!

Now, the first thing we’re going to do is right there in your home directory, simply make a directory tree with the following command:

tree -d

tree -d

That will make a lovely tree. The -d flag means that it will only show directories in the output. That’s what we wanted, a directory tree. However…

You can make a tree with the files included. Just drop the -d flag and try this:

tree

tree

Now, let’s send that output to a file. If you want a tree (with or without files listed in it) as a saved text file, you can try this command:

tree > tree.txt

1	tree > tree.txt

Now, for some fun, you can try this (it will take a long time):

cd /
sudo tree > root_tree.txt

1 2	cd / sudo tree > root_tree.txt

You need ‘sudo’ for that command so that it can traverse and list the various directories for which you have no permissions. It will take a long time. I want to say that it took about 30 minutes, but I currently have a bunch of external stuff hooked up to this device.

It will also generate a giant text file. Mine was over 500 MB in size. Opening it is a slow and painful process, but it’s not too bad once it is open. There are other options for the tree command, just type man tree to learn more about the tree command.

Closure:

So, now you know how to create a directory tree. You also know how to make your directory tree include files and how to make a directory tree of your entire computer’s file system. I don’t know why you’d need to know this, but now you do. They do make good text documents for small sections of the tree, especially if you need to quickly see the directory structure for some other task.

List The Files In A Directory

Today’s article is only going to be useful if you are a new user and don’t yet know how to list files in a directory. This is, of course, something you do in a terminal. I do believe this will be a quick and easy article, so read on if you don’t yet know how to list files in a directory.

If you’ve used Linux for more than a month, you can safely ignore this article.

Yes, this has been covered all over the web. This isn’t anything remotely new, nor is it anything all that complicated. However, this is a holiday weekend and I figure it’s a good article for new users who happen to be just browsing around. I’ve also covered some ‘ls’ commands before.

On the other hand, it should be a short article! So, there’s that!

List The Files In A Directory:

Of course, this article requires an open terminal, like many other articles on this site. Should you not know how to open the terminal, you can do so with your keyboard. Press CTRL + ALT + T and your default terminal should open.

With that terminal now open, let’s try a simple command:

ls

That will list all the files in the directory. If you’d like to see the output in columns, you can always try this command which lists the output in a denser manner.

ls -l

ls -l

That command doesn’t list dot (hidden) files. Seeing as you’re in the home directory, you should have some hidden files. If you want to use the ‘ls’ command to show files, you need the -a flag. You can combine it with the above and use this command:

ls -la

ls -la

That’s the command I use more often than not. This being Linux, you get to decide which how to use the command. I think I type the ‘ls -la‘ command out of habit.

Closure:

Well, you got an article. Sure, it’s a simple article but someone may find this important information. Of course, they could just use the man page – but what’s the fun in that?