This is the second part of my Effective Shell series, which contains practical tips for using the shell to help with every day tasks and be more efficient:
- Part 1: Navigating the Command Line
- Part 2: Become a Clipboard Gymnast
- Part 3: Getting Help
- Part 4: Moving Around
- Part 5: Interlude - Understanding the Shell
- Part 6: Everything You Don't Need to Know About Job Control
- Part 7: The Subtleties of Shell Commands
In this article I'll show you how you can use the shell as an efficient tool to compliment how you use the clipboard.
Note for Linux Users: In this article I'll use the
pbpaste commands to access the clipboard, which are available on a Mac only. To get access to the same commands on other platforms, check Appendix: Clipboard Access on Linux.
Use the Shell on the Clipboard
You can easily use shell commands on the contents of your clipboard. Just use
pbpaste to output the clipboard, run the output through some commands, then use
pbcopy to copy the result.
Try copying the following text:
Kirk Van Houten Timothy Lovejoy Artie Ziff
Then in the shell, run:
You should see the contents of the clipboard. Now we'll look at some ways that shell access to the clipboard can help with common tasks.
Don't you hate it when you have to copy formatted text and don't have an easy way to paste it as unformatted text? Here's an example, I want to copy this Wikipedia page on ‘bash’, and paste it into a Word document:
Many programs have a shortcut to paste the contents of the clipboard (such as ‘command + shift + v’) but if you are like me you might find yourself pasting into a plain text editor just to copy out the plain text.
If you just run the command
pbpaste | pbcopy, you can easily strip the formatting:
We're just piping out the clipboard (which ends up as plain text, cause we're in a terminal!) and then piping that plain text back into the clipboard, replacing the formatted text which was there before.
This little trick can be very useful. But we can use the same pattern to quickly manipulate the contents of the clipboard in more sophisticated ways.
Let's say someone has emailed me a list of people I need to invite to an event:
The problem is:
- The list is in Excel and is formatted
- The list has duplicates
- I need to turn each name into an email address like 'Artie_Ziff@simpsons.com’
And I want to email everyone quickly.
We can quickly handle this task without leaving the shell.
Copy the raw text below if you want to try out the same commands and follow along:
Artie Ziff Kirk Van Houten Timothy Lovejoy Artie Ziff Nick Riviera Seymore Skinner Hank Scorpio Timothy Lovejoy John Frink Cletus Spuckler Ruth Powers Artie Ziff Agnes Skinner Helen Lovejoy
First, we copy the text to the clipboard.
Now we can paste and sort:
$ pbpaste | sort Agnes Skinner Artie Ziff Artie Ziff Artie Ziff Cletus Spuckler Hank Scorpio Helen Lovejoy John Frink Kirk Van Houten Nick Riviera Ruth Powers Seymore Skinner Timothy Lovejoy Timothy Lovejoy
Then remove the duplicates:
$ pbpaste | sort | uniq Agnes Skinner Artie Ziff Cletus Spuckler Hank Scorpio Helen Lovejoy John Frink Kirk Van Houten Nick Riviera Ruth Powers Seymore Skinner Timothy Lovejoy
Replace the underscore with an ampersand:
$ pbpaste | sort | uniq | tr " " "_" Agnes_Skinner Artie_Ziff Cletus_Spuckler Hank_Scorpio Helen_Lovejoy John_Frink Kirk_Van_Houten Nick_Riviera Ruth_Powers Seymore_Skinner Timothy_Lovejoy
Then add the final part of the email address:
$ pbpaste | sort | uniq | tr " " "_" | sed 'firstname.lastname@example.org/' Agnes_Skinner@simpsons.com Artie_Ziff@simpsons.com Cletus_Spuckler@simpsons.com Hank_Scorpio@simpsons.com Helen_Lovejoy@simpsons.com John_Frink@simpsons.com Kirk_Van_Houten@simpsons.com Nick_Riviera@simpsons.com Ruth_Powers@simpsons.com Seymore_Skinner@simpsons.com Timothy_Lovejoy@simpsons.com
This looks perfect! We can now put the transformed text back onto the clipboard:
$ pbpaste | sort | uniq | tr ' ' '_' | sed 'email@example.com' | pbcopy
All in all we have the following pipeline:
pbpaste- output the clipboard
sort- order the output
uniq- deduplicate the rows
tr ' ' '_'- replace spaces with underscores
sed /$/@simpsons.com- add the email domain to the end of the row
Building this in one go is hard, let's look at little more at the pipeline.
Thinking in Pipelines
Some of these commands might be unfamiliar, some might not make sense, and you might be thinking ‘how would I remember that’. Actually, there are many ways to solve the problem above, this is the one I came up with by iteratively changing my input text.
Here's what I mean - you'll see that I actually build a pipeline like this step-by-step:
You can see in the screenshots that I start simple, and step by step add the stages we need.
(P.S - if you are wondering how I am jumping backwards and forwards a word at a time, check the last chapter ‘Navigating the Command Line').
What we're doing here is only possible because these simple commands all follow ‘the Unix Philosophy’. They do one thing well, and each command expects it's input to become the input of another command later on. Specifically:
- The commands are primitive and simple -
sortis sorting a list,
uniqis making elements unique.
- The commands don't produce unnecessary output -
sortdoesn't add a header such as
Sorted Items, which is great because otherwise it would clutter our pipeline.
- We are chaining commands together, the output of one becomes the input of another.
We don't need a command such as ‘Take a muddy list, sort and clean it, then turn pairs of words into an email address’ - with a few simple ‘workhorse’ commands we can easily build this functionality ourselves.
These workhorse commands will be introduced and detailed as we go through the series. We'll also spend a lot more time looking at pipelines.
I hope this was useful! Please comment if you have any questions or tips. To see further articles as they come out, follow the repo at:
Or just follow @dwmkerr on Twitter.
Appendix - Clipboard Access on Linux
If you are using Linux, there is no
pbpaste commands. You can use the
xclip tool to create equivalent commands.
sudo apt-get install -y xclip
Then add the following to your
# Create mac style aliases for clipboard access. alias pbcopy="xclip -selection c" alias pbpaste="xclip -selection c -o"
Obviously you can use any alias you like! The article assumes that
pbpaste have been used.