terminal Archives • Page 3 of 9 • Linux Tips

Let’s Let AI Write An Article About ‘sed’

Today’s article is going to be about ‘sed’. However, I’ll be letting AI write it, just so we have an excuse to play with ChatGPT. I love new tech and I’m going to go against the advice given and just post the resulting article directly.

Also, I picked ‘sed’ as an article topic because it’s a pain in the butt to explain even the basics. It’s such a powerful tool that knowing where to start can be tough. As such, I’ve decided it’s a perfect article for testing AI. I will only be formatting the suggested article.

Hey, it was this or write a meta article. I hadn’t written one for February and this will be the last article in February. Not much had changed, though we did cross some milestones, and I figured this article would be even more interesting to my readers.

Again, if there are errors, I am not to blame. I am posting the entire output after asking ChatGPT to write the article. I am only editing for the format. So, read on to see how AI is coming along. Hint: It’s doing well! It’s coming along nicely!

About ‘sed’:

“sed” is a stream editor in the Unix-like operating systems. It is used to perform basic text transformations on an input stream (a file or input from a pipeline). The sed command reads the specified files, or standard input if no files are specified, and applies the transformations which have been specified.

The syntax for using sed is:

sed [OPTIONS] 'COMMANDS' [INPUTFILE(s)]

1	sed [OPTIONS] 'COMMANDS' [INPUTFILE(s)]

Where OPTIONS can be any of the options available in the man page and COMMANDS are the instructions that tell sed what transformations to perform on the input.

One of the most common uses of sed is to replace strings. The basic syntax for string substitution is:

sed 's/old-text/new-text/' [INPUTFILE(s)]

1	sed 's/old-text/new-text/' [INPUTFILE(s)]

Where old-text is the text you want to replace, and new-text is the text you want to replace it with. For example, to replace the word “apple” with “banana” in the file “fruits.txt”, the following command could be used:

sed 's/apple/banana/' fruits.txt

1	sed 's/apple/banana/' fruits.txt

You can also use regular expressions in the old-text argument to match a more complex pattern. For example, to replace all occurrences of “apple” or “Apple” with “banana”, the following command could be used:

sed 's/\(apple\|Apple\)/banana/' fruits.txt

1	sed 's/\(apple\\|Apple\)/banana/' fruits.txt

Another common use of sed is to delete lines. To delete a line, you can use the d command. For example, to delete the first line of the file “fruits.txt”, the following command could be used:

sed '1d' fruits.txt

1	sed '1d' fruits.txt

To delete multiple lines, specify the line numbers separated by a comma. For example, to delete lines 1 to 3 in the file “fruits.txt”, the following command could be used:

sed '1,3d' fruits.txt

1	sed '1,3d' fruits.txt

sed also supports multiple commands in a single execution. Simply separate the commands with a semicolon (;). For example, to delete the first line and replace “apple” with “banana” in the file “fruits.txt”, the following command could be used:

sed '1d;s/apple/banana/' fruits.txt

1	sed '1d;s/apple/banana/' fruits.txt

In addition to the commands mentioned above, there are many other powerful commands available in sed, such as inserting text, printing selected lines, and more. To learn more about these commands and other features of sed, consult the man page by running man sed in your terminal.

In conclusion, the sed command is a useful tool for performing basic text transformations on files or input from a pipeline. Its syntax is straightforward, and its wide range of commands makes it versatile enough to handle a variety of text manipulation tasks.

Closure:

There you have it. You have an article about sed – and it wasn’t written by me. So, what do you think of it? Do you think I can hang up my hat and just let AI write my articles from here on out? Do you spot any mistakes? It’s supposed to be an overview, not a complete dissertation. I think it does surprisingly well!

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.

Clear The Terminal

Today’s article will be a nice and easy article, where we learn how to clear the terminal. That is, we will clear any typed text and returned information from the terminal. This will be a nice and quick article.

I am feeling like garbage today and I still need to edit the last article. Ugh… But, the show must go on!

This is what I get for not having scheduled a few articles ahead. Fortunately, I have short articles in mind. Today is a good day for just that.

It should be noted that clearing the screen doesn’t delete your scrollback history. Someone could come along and use the up arrow to see your previously typed commands. If you’re at your workstation then I guess you could consider this a privacy measure – but it certainly shouldn’t be considered much of a security measure.

So, as I said, it’ll be a short article. Let’s just jump into it…

Clear The Terminal:

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.

Now, let’s generate some content… Run the following:

ls && uptime

1	ls && uptime

That should fill up your terminal with stuff. Now, let’s clear the terminal. Type the following command:

clear

clear

Tada!

But wait, there’s more!

Run those commands again. This time, and this appears to be pretty universal, just use your keyboard and press CTRL + L.

See? It does the same thing as you get when you type clear. Those are two ways for you to use when you want to clear the terminal.

Closure:

Yup… You’ve learned how to clear the terminal. I told you that it’d be a short article. It’s even an easy article. Now I’m going to lie down and hope for a nap.

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:

uptime

uptime

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:

lshw

lshw

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:

sudo !!

sudo !!

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!

How To: Terminate A Terminal Command

Today’s article is going to be a very brief article, prompted by a question on one of the Linux support forums about how to terminate a terminal command. The poster got an answer, but it was the additional comments that made me realize how few people know how to properly terminate a terminal command – specifically new users.

So, if you want to learn how to terminate a terminal command, read on!

As I said, this isn’t going to be a very long article. I have actually covered this before in another article – but it kinda deserves its own page/article. It’s not a very long and detailed exercise, but it kind of got lost in the mix and I’m compelled to write this article.

I want to make sure that this information is easily found via search engines because the answers I saw to this question included things like ‘just wait’ or ‘start another terminal, just close that one’. None of those are the ‘right’ answer to the question. None of those are the proper way to terminate a terminal command.

So, let’s see if I can turn this tiny command into a full article about…

How To Terminate A Terminal Command:

Let’s use the ‘ping’ command as our tool of choice for this exercise. If you type in the following, you’ll continue pinging my site until you tell it to stop.

ping linux-tips.us

1	ping linux-tips.us

Of course, you can limit the number of pings you send. That’s easy enough. If you wanted to ‘ping’ linux-tips.us five times, you’d run this command:

ping linux-tips.us -c 5

1	ping linux-tips.us -c 5

The output of which looks similar to:

pinging this site just five times before stopping. — That’s how you properly limit the number of pings to linux-tips.us. Pretty easy, right!?!

But, you can run the first ‘ping’ command and just tell it to stop running whenever you want. The command to do so is:

CTRL + C

The output of this would look similar to this:

So, if you want to stop a running terminal command, it’s pretty easy. You just need to press CTRL + C on your keyboard and the process will stop. You will have terminated a terminal command the right way.

Note: You don’t always want to terminate processes. Things like terminating a device that’s in the process of upgrading may lead to an unstable condition. Then, for example, terminating a write operation may result in a loss of data.

Processes like that normally shouldn’t be stopped. In those cases, it’s best to just let the computer finish what it is doing – unless, of course, you do need to stop them because you have reasons to do so (like you started writing to the wrong device).

Closure:

Huh… I managed to kinda turn it into a full article, so there’s that. It really is a simple concept and the shortcut to terminate a terminal process is easy enough to remember. In an ideal world, this article will rank well in the search engines and save new Linux users time and effort. I’m not sure if I should aim for ‘terminate’ or ‘stop’, but this needs to be common knowledge – or more widely known than it seems to be at the present.

Also, just because you closed the terminal where you started the process doesn’t mean the process itself has necessarily ended. So, there’s something else to keep in mind. A process can and will happily keep executing even though you’ve closed the terminal. Linux is like that!

I wasn’t really sure that I could fluff this up into a complete article, but it appears that I’ve kinda pretended to do just that! Well, you’ll have another article in just a couple of days. It’ll probably be more involved than this one! This one is all about that CTRL + C function.

Pause And Unpause Your Terminal

Today, we’re going to learn how to pause and unpause your terminal. This will be one of the easiest articles I’ve ever written. It may also be one of the shortest! So, to learn how to pause and unpause your terminal, read on!

In fact, this information is so brief, I’m not quite sure how to turn it into a ‘full-fledged’ article. There’s really not all that much to it, but it’s information that should probably be on the site somewhere, and that somewhere might as well be here.

For many of us, we’ve learned that pressing CTRL + S will save whatever it is we’re working on. Well, that’s not the behavior you’ll see in the terminal – and from my testing, this appears pretty universal.

If you press CTRL + S while in the terminal, which a new person may do by accident, it pauses the screen – making the screen appear as though it is locked. This can be confusing, especially to a new Linux user that’s not accustomed to using the terminal.

There’s no obvious way to unlock the screen. There’s no tooltip or anything like that involved, so a new person may just end up closing their terminal and opening a new one. You don’t have to close the terminal and start a new one.

Well, you can press CTRL + Q and that will unlock the screen. That’s really all there is to it – but there’s a caveat.

Pause And Unpause Your Terminal – CAVEAT:

Anything typed on the screen, any inputs entered in that terminal, will appear (and function) when you unpause the screen. This could be risky if someone has had access to the computer while you were away. Pausing the terminal in no way should be considered a security measure.

For example, press CTRL + S in an open terminal. Then type the following:

uptime

uptime

Next, press the ENTER button.

Finally, press CTRL + Q.

When you press that key combination, you’ll see that the ‘uptime’ command is going to be, and will be, executed. So, this isn’t even anything remotely secure. It’s useful for pausing when there’s a lot of information being fed to the terminal, and that’s about it.

As far as I can tell, it’s more likely to be used by accident, tripping up new Linux users who may have hit the keys by accident or hit them thinking they’re saving something.

Closure:

Well, that’s about as long as I can make this article without padding it for Google’s sake. It really doesn’t need to be longer than this to show you how to pause and unpause your terminal. It’s really just a simple matter to unpause the terminal without needing to open a new instance.