Save A Command’s Output To A File (While Showing It In The Terminal)

The title is the best I can come up with to describe this exercise as we’re going to save a command’s output to a file – while showing that same output in the terminal. This is something we’ve not quite done on this site before and something you might find interesting.

NOTE: This article assumes that you’re using Bash.

We’ve sort of covered redirect operators before. Read this article:

How To: Write Text To A File From The Terminal with “>” and “>>”

However, this time, you’re going to enter a command and see the output in the terminal, unlike what you’d see in the above-linked article. On top of that, you will simultaneously save that output to a file.

This can be handy to keep track of a command’s output over time. This can also be handy if you’re trying to audit a system and want to keep track of the output from the command.

For this article, we’re going to just use a simple example command. We’ll be making use of the uptime command because it’s easy and universal. If you’re using a desktop (or server) Linux, you have this command available.

How To: Find Your Uptime In Linux

This article is also going to make use of the tee command. If you’re a regular reader, you’ll know we’ve covered this command before. Then again, if you’re not a regular reader, you can just as easily learn about the tee command by reading the following article:

Mastering The Power Of Linux Tee Command

We’ll also be using the terminal, of course. We almost always use the terminal!

Save A Command’s Output To A File:

As suggested above, this is another article that relies on an open terminal. You can usually open a terminal by pressing CTRL + ALT + T on your keyboard. A terminal is otherwise available in your application menu.

With your terminal open, let’s just view your uptime with this command:

Next, we’re going to tell the command to show the output AND save the output to a file. That’s quite simple:

So, let’s try this example command:

Now, you can verify that this worked with this command:

Every time you run that command, it will clear out the existing text and write the most recent output to the uptime.txt file.

If you’d rather append the data, that’s easily done. It looks like this:

Again, as a handy example:

If you run that command multiple times and then check it with cat uptime.txt you’ll see that the -a flag will append the output. So, each time you run this command it will add the new output to the file.

That’s all there is to it. This is a handy thing if you want to monitor the output of a command over a period of time. You can alias the uptime command to this command and have a record of all the times you ran the uptime command in the terminal.

I’m sure there’s more that you can do with it, but that’s a basic idea that you can take with you. It’s a pretty handy command and one that I recently shared via PM with a Linux.org user. Seeing as it was on my mind, I figured I’d make it an article. I’d call it a ‘short’ article but the title was already too darned long!

Closure:

Now you know how to save a command’s output to a file while also showing the command’s output in the terminal itself. This is a handy enough command and easy enough to do. It seemed like it’d make an easy article for folks, so I wrote it. I don’t have any other justification, though it was not all that taxing to write.

In my defense, I deserve an easy article now and then!

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Rerun The Previous Terminal Command

Today’s article should be simple enough, where we’ll just be covering how to rerun the previous terminal command. This will be something many new Linux users won’t know about, and may come in handy. If you want to learn how to rerun the previous terminal command, read on!

This is another one of those short articles where I just try to share something basic in hopes of people seeing it. The more advanced Linux users are already aware of this command, but new users are unlikely to know unless they’ve been reading books or taking lessons online somewhere.

So, what we’ll be doing is running a terminal command – but we’re also going to show you how you can use this to modify a previous terminal command. I’ll try to give you an example of when you might want to do so.

It will not be complicated. It should also be remarkably short. I really don’t think I can fluff this out to be all that long… 

So then, let’s learn how to rerun the previous terminal command…

Rerun The Previous Terminal Command:

Obviously, this is going to require an open terminal. That’s easy enough. Just open your favorite terminal or just press CTRL + ALT + T and your default terminal should open.

With your terminal open, let’s check your uptime. To do that, you just run this command, like so:

If you wanted to run the command over again, there are a number of ways to do so. But, we’ll be using ‘!!’ to run it over again. To run uptime over again, just enter this command:

Sure enough, it runs the uptime command all over again. See? You’ve already learned how to rerun the previous terminal command. But, wait, there’s more!

Let’s say you wanted to check out your hardware and you ran this command:

If you pay attention to the output from that command, it suggests you run the program with elevated permissions, like with sudo. To rerun the previous terminal command as sudo, you can just run:

Pretty neat, huh? You can do alsost anything before rerunning the previous terminal command, like changing the directory, making a directory if you forgot to, or adding a command you forgot the first time.

Closure:

Well, there you have it. It’s another article! I couldn’t make this a longer article, try as I might. That’s okay, you’ve now learned how to rerun the previous terminal command and how to modify it. A short article is better than no article, which is nice!

NOTE: Yes, you can do it in reverse. If you type ‘sudo‘ and hit the enter button, you can then type ‘!! lshw‘ and run the command as ‘sudo lshw‘. It’s pretty neat and not something everyone is aware of. Well, now you know – and knowledge is power!

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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