Tag: file management

How To: Show File Sizes When Listing Files In A Directory

Today we’re going to have an easy article that shows you how to show file sizes when listing files in a directory. It’s a simple set of commands and easy enough for a newbie to learn. Though the title is unwieldy, read on to learn how to show file sizes when listing files in a directory…

We’ll be using the ‘ls’ command for this exercise. Like normal, I’ll go ahead and suggest you read this page about why you shouldn’t parse the output from the ‘ls’ command. There are better ways and that link will explain it, and what you should consider, far better than I can.

Anyhow, the ‘ls’ command defines itself as:

ls – list directory contents

Of course, regular readers will recognize the ls command as we’ve used it numerous times before. Even though you shouldn’t parse the output from the command doesn’t mean it’s not still useful for a variety of other tasks.

Today, we’ll be exploring one of those tasks. We’re going to show you how to show file sizes when listing files in a directory – specifically with the ls command. Don’t worry, you won’t need to install anything. If you’re using any desktop Linux distro, the ls command is certainly available to you by default.

For the record, you should probably view the ls man page (run man ls in the terminal) to learn more about the command. It’s still a useful command – and I do sometimes parse the output from the command, but only when nobody is looking and when the output isn’t all that vital. I use grep with the ls command almost every day! Shh!!!

Show File Sizes When Listing Files In A Directory:

(That’s an unwieldy title!)

Anyhow, it’s the ls command. That’s a terminal-based command. So, of course, you’re going to need an open terminal (like so many of these articles). Press CTRL + ALT + T and your default terminal should open. Tada!

With your terminal now open, we can just use your home folder. To run the basic ls command, it’s just that:

Now, to show file sizes when listing files in a directory, you’d start with the -s flag:

You may find the output from that command is relatively useless without doing a bit of math to go along with it. Fortunately, you can tell the command to show the file size in a ‘human-readable format’. To do that, you’d run this command with the -h flag:

Now, if you wanted to show all the files, including the hidden files in that directory, you’d just add the -a flag. The command would look like this:

And if I was a Linux newbie, that’s the command I’d commit to memory. It doesn’t make a mess. The output is still plenty clear. It’s easy to understand. It’s easy to remember and turn into a habit. This way, when you ran the ls command, you just default to using -ash flags.

If you don’t want columns (and some do not), and you want more information such as file permissions or ownership values, you can just add an -lflag to the above. That’d look like:

So, it’s up to you…

You can remember ‘ash’ or you can remember ‘lash’. You can also not remember either and ignore the flags completely, but I find developing a habit is a good way to remember things. It’s your device, you do what you want!

Closure:

There you have it! You have another article. This one was simple enough and I hope you found it useful. If you’re new and running the ls command is new to you, it’s worth learning some additional flags and gathering more information at a glance. That’s why there’s this relatively simple article that shows you how to show file sizes when listing files in a directory.

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Rename A File Downloaded With ‘wget’

In today’s article, we’re going to learn how to rename a file downloaded with ‘wget’. This will not be a complicated article. It will also be a pretty short article. If you want to learn how to rename a file downloaded with ‘wget’, read on and you’ll see how!

Often, you’ll use ‘wget’ to download a file and it will have some sort of convoluted file name. You can download a file with ‘wget’ and rename it automatically. If this is something you’re interested in doing, we’ll learn how to do it in this article.

We’ve used ‘wget before. See:

How To: Hide The Output From wget
Make wget Use IPv4 or IPv6
How To: Make ‘wget’ Ignore Certificate Errors

We’ve used ‘wget’ in other articles, so feel free to use the search function to see the other articles about ‘wget’.

If you’re curious, you can check the man page. You’ll see ‘wget’ defines itself as:

Wget – The non-interactive network downloader.

That’s a good enough description, I suppose. Basically, you use ‘wget’ in the terminal to download files. It’s a pretty handy application and, importantly, a pretty universal application. If you’re using a GNU/Linux desktop (or server), you’ve almost certainly got ‘wget’ as an available tool.

So then…

Rename A File Downloaded With ‘wget’:

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.

Let’s ensure you have ‘wget’ installed with:

If ‘wget’ is not installed, install it from your package manager. Once installed, you can take it on a test run:

Now, we’re going to make ‘wget’ keep trying in case the download has issues. We’ll use the -c (continue) flag:

You probably don’t need the -c flag for this file, but it’s a good habit to get into. If we add the -O flag (for output-document) to the command, it’d look like this:

Or, to try to make it more clear:

In the latter example, you’ll have downloaded the file and renamed it to numbers.txt instead of saving it as the original filename. See? Pretty simple!

Closure:

There you have it. You have a new article. This time, we’ve learned how to rename a file downloaded with wget. It’s a handy trick to keep in mind, as people tend to want to give their files names with things like version information and all that. If you want a simpler file name, this is a nice easy way to do it.

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Disallow Directory Listing (in the terminal)

In today’s article, and for no apparent reason, we’re going to learn how to disallow directory listing in the terminal. This seems like a good article for beginners to learn, and it seems like something most folks might like to know. So, if you want to disallow directory listing read on!

You never know when you might want some additional privacy, though I’d definitely not confuse this for strong privacy measures like encryption, amongst your files. Perhaps you’re planning on releasing a memo and you don’t want anyone to read it until you’re done?

I dunno? It’s up to you as to why you’d want the potential privacy from making it so that the files in a directory can’t be listed. Your reasons are your own. I just share tidbits of knowledge.

We will be using ‘chmod’ in this exercise. The man page for ‘chmod’ describes itself like:

chmod – change file mode bits

But, for our purposes and generally speaking, it’s used to adjust the file permissions. As you should know, files have various permissions in Linux – and everything in Linux is a file. There are read, write, and executable bits that can be set (with said chmod, for example) and there’s also file ownership (for another day). We’ll be using those permissions to prevent listing the files in a directory.

Ready? It really won’t take long – and it should be easy enough for anyone…

Disallow Directory Listing:

As the title suggests, this is another ‘in the terminal’ application. So, of course, you’ll need an open terminal. You should open a terminal now. 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, let’s first start by making a directory – just so that we can then use that to disallow directory listing. We’ll just do this in your /home directory. Start with:

Now, let’s move to the new ‘sample’ directory and make a couple of files.

Now, what we’re going to do is change the permissions of the ‘sample’ directory, like so:

You don’t need ‘sudo’ or anything, because these files belong to you. But, you can now test it. While still in the folder, try any of the following:

Or (from outside the directory, if you’d like):

In all cases, it should give you a ‘permission denied’ error, because you no longer have permission to list files from within that directory.

If you wish to reverse this, you can simply try changing the permissions again. You can just:

With that command, you can resume directory listing. So, it’s pretty easy to reverse the process. It’s also not the greatest security measure you can take, because of that. So, do what you will with it, as you now know how to disallow directory listing in the terminal.

Closure:

There you have it, it’s yet another article. This one seemed like an interesting one to write, so I figured I’d write it. You never know when you want to disallow directory listing, but now you know how to do so. If you have any questions, feel free to ask…

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.

Let’s Learn A Little About The ‘dir’ Command

In today’s article, we’re going to learn about the ‘dir’ command. The ‘dir’ and ‘ls’ command are quite similar, but ‘ls’ seems to get all the press. So, today we’ll be looking at the ‘dir’ command. It will be a relatively short article (I suppose) and easy enough for new people to follow.

You’re possibly already familiar with the ‘ls’ command. I’ve written a variety of articles about ‘ls’. We’ve used ‘ls’ in numerous articles along the way. Here are a couple of ‘ls’ articles:

Some Fun With Sorting The Output Of ‘ls’
Let’s Use ‘ls’ To Sort Files By Time

Those are just a couple. WordPress, the backbone of this site, isn’t very good at searching for just two characters like ‘ls’. That’s for good reason and I’m not sure if that behavior can be changed.

Ah well… Root around and I’m sure you’ll find more. I’ve written about 300 articles and can’t possibly remember them all!

Anyhow, we’ll be using the ‘dir’ command in this article. It describes itself pretty well in the man pages, and is similar to the ‘ls’ command. It describes itself as:

dir – list directory contents

So, if you’re familiar with the ‘ls’ command, you’ll find ‘dir’ to be quite similar. I’m sure there’s a reason that both exist – I’m just not sure what that reason is, nor am I sure why both are included by default. Feel free to let me know your thoughts or theories!

Edit: See this link to see why Linux contains both.

Well then, let’s get on with it…

The ‘dir’ Command:

Well, you shouldn’t need to install anything for this article, but you will need to have an open terminal. By now, you know how to open the terminal if you’re a regular reader, but others need only press CTRL + ALT + T and their default terminal should open.

With your terminal now open, let’s just start with the basics. If you just enter the ‘dir’ command it will output a list of all the visible files in that directory. It looks like:

You can also specify a directory, like:

If you want to show hidden files, you can try this:

If you want to list things in a single column, in a list format, you can just add the -l flag. This also shows the file’s permissions and modification time. So, you could try:

If you want to list files with the ‘dir’ command and to do so recursively (digging into the folders within folders), you can do that too. All you need is the -R flag. So, for example:

That’s just scratching the surface of the ‘dir’ command. There’s a whole lot more that you can do, so just try the man page for more nifty tricks  you can do with ‘dir’.

If you have any questions or nifty ‘dir’ information, please feel free to leave a comment. It’s a pretty handy command to have on hand, much like ‘ls’.

Closure:

And there you have it. You have yet another new article, this one about the ‘dir’ command. It’s not terribly complicated and it’s another tool to toss into your toolbox. You never know when you might want to use it instead of the ‘ls’ command, though they’re awfully similar.

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.

Find And Remove Duplicate Files With rdfind

In today’s article, we’re going to find and remove duplicate files with rdfind. We’ll try to make this as safe as possible. I’d suggest newer  users not actually worry about duplicate files. Allocate enough space to your OS and don’t worry about it. Disk space is cheap these days.

Warning: Blindly removing duplicate files can be a risky operation. It can break things. You have been warned. Exercise caution!

If you’re interested in removing duplicate files, then the rdfind application is one solution you can try. There are others, but we’ll be using rdfind. We may cover other choices in the future.

You don’t have to run rdfind with it automatically deleting the duplicate files and that’s what I’m going to suggest you do – at least at first. It’s good to see what’ll be deleted before it is actually deleted.

If you check the rdfind man page, you’ll see it’s described as:

rdfind – finds duplicate files

It does what it says on the tin. It finds duplicate files. You can run the command in a manner that automatically removes the found duplicates, but that’s not something to take lightly.

Again, and I can’t stress this enough, some duplicates are there for a reason – they belong there. So, don’t run this on the root directory and expect a good outcome. Running this on the root directory and automatically removing duplicates is going to break stuff. Feel free to do so, ’cause it’s your computer. Just don’t blame me when it breaks.

There… I feel you’re safely and properly informed! Let’s get this article started…

Install rdfind:

We’ll just use the terminal to install rdfind. To open your default terminal emulator, press CTRL + ALT + T and your default terminal should open. You might as well leave it open, as rdfind also runs in the terminal and you’ll need an open terminal in the next step.

Debian/Ubuntu:
Arch/Derivatives:
RHEL/CentOS:
Fedora/Derivatives:

Now that you have installed rdfind, you should probably consult the man page. That’s an easy command:

With that knowledge fresh in your memory and rdfind installed, we can just jump into the article!

Find And Remove Duplicate Files With rdfind:

Your terminal should still be open from the previous step. If not, go ahead and open it now. You’ll need a terminal open to find and remove duplicate files with rdfind. It is not a graphical application.

So, I suppose you can start with this command:

That may look dangerous, but it’s not. If you run that command, it simply finds the duplicate files and then creates a text file for you. You then review the text file and manually remove the duplicate files. This is probably for the best. It’s also the same thing if you do a dry run, like so:

You can actually delete the files and replace the first one found with hard links. While not recommended by me, it’s at least safer.

Finally, you can just go right ahead and just find and remove duplicate files! This is safer if you have both a recent backup and you’ve gone ahead and run one of the first two commands. Then, if you have run one of those two rdfind commands, you’ll know what’s going to be deleted.

Just don’t run rdfind on your root directory, and probably don’t run it directly on your home directory, and you should be more or less okay. Feel free to run it on your Downloads folder, on your Documents folder, or even your Pictures folder.

Running rdfind that way, on those types of directories, will be fine and at least should not break things. Rdfind pretty good at finding just duplicates, or I’d not recommend it. Be sure to backup first and make sure you give it a dry run before you start automatically removing stuff! Seriously, do not run this on your root directory.

Closure:

And there you have it… You have yet another article! This time, we’ve learned how to find and remove duplicate files with rdfind. You were given a clear warning, but you’re gonna do what you’re gonna do. Man, I really need to write that article about backing up properly!

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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