hpr-knowledge-base/hpr_transcripts/hpr2333.txt

Episode: 2333
Title: HPR2333: VirtualenvWrapper for Fish Shell
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr2333/hpr2333.mp3
Transcribed: 2025-10-19 01:25:41

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This is HBR episode 2,333 entitled Virtual and Rapper for Fish Shell.
It is hosted by me and is about 14 minutes long and can remain an explicit flag.
The summary is in this episode talk about how I created my own Virtual and Rapper like interface using Fish Shell.
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Hello Hacker Public Radio fans, this is Be Easy once again.
I'm going to do a quick little episode in response to BJB's excellent story about Virtual and Rapper.
She did a great job in explaining it. I learned a lot.
She briefly talked about how you can do Virtual and other shells.
She wanted to keep her shell tight and succinct and I think she did a great job doing that.
I'm going to go into how I use a Virtual and Rapper for Fish Shell.
For anyone who is not familiar with Fish Shell, Fish Shell is an alternative to Bash.
It's ManPage C. It is called, oh that's it, this is it.
Fish Shell is a smart user friendly command line shell for Mac OS Linux and the rest of the family.
I've been using Fish for a couple of years now because I really like how it does auto completion.
It has a nice little set of plugins and a nice ecosystem around it.
I have actually started to script a little bit and usually I script in Bash just because I'm more familiar with Bash scripting.
I have had an opportunity to do some scripting in Fish as well.
It's not as robust of a scripting language but it's much more useful, at least my opinion, much more useful shell.
But one thing it doesn't have is it doesn't have a way to run Virtual and Rapper.
I first fell out about Virtual and I've been using Python for a couple of years now as well.
I've been using Virtual Environments for that entire time and I've just been finding my file and the source that directory been activate.
And I always saw in that and when you do that there's always another file in there called Activate Fish and another one is called Activate.csh.
So I didn't know there were four but I figured out later when I switched to Fish Shell that yeah, if you did source, been Activate.Fish, it would actually activate your fish.
It's just a virtual environment in your Fish Shell in a similar manner as it does for Bash.
But there was no real way to do it easily.
So after I started to research Virtual of Rapper, how could I have a similar API to that? I could have similar commands to that.
So I've updated my Fish config file and I want to go over right now the edits that I've made to that Fish config file to make it so that I have similar functionality.
So the function I'm talking about is a way to easily with a single command switch to a virtual environment, easily create a virtual environment and destroy one.
And then one extra thing that I made was a way to list all the virtual environments that I have in Active right now.
So inside of my Fish Shell I guess to get there I have to go cd.config.fish
So then cd.config.flashfish and then I'm just going to go vim config.fish.
And so inside of my, and I'm going to put this in the show notes inside of my virtual environment, I have a lot of things inside of my config.
I have a lot of things going on, but one of the first things I do is I do a set-dash X and all caps virtual underscore all underscore disable underscore prompt one.
And that's a way to, because I'm using a custom power line show, I'm telling default fish to not use its way of adding a virtual long notification, usually in basher and fish inside of parentheses you'll see what the virtual environment you're currently in.
And I turned it off because the, the power line that I'm using shows which virtual environment in all of writing, so it's kind of redundant.
And I am including, I think either as a cover picture inside the show notes, a picture of what it looks like when I'm in a virtual environment.
So, so I, I used and BJB talked about this a little bit about how to use aliases and I, and you can use aliases and functions in fish shell as well.
And so, for this purpose, I also made another, another item called export set on the export set all caps work on underscore home equals my home directory slash ENVS.
And that's my, so I store all my, I want to store all my virtual environments in this directory.
And so, I have a aliases called LSEMVS, which is list LS owns, and that's a way for me to list all my virtual environments.
And what I'm, and what I'm doing here is I'm running this aliases, I'm doing LS, LS-EMVS.
And then dollar sign will go on home, pipe that into said, and I'm removing a backslash out of there in my said command.
And what that is doing the LS-EMVS, if you don't know about that, it actually adds a comma.
It puts all of your list on that LS command comma separated.
So, when I run the said command, it takes out, there's a extra backslash, there's extra forward slash at the end of, at the end of every one of those directories.
So, I don't want to see that extra forward slash. So, I just say said, you know, s, forward slash, backslash, forward slash, forward slash, g.
And that's the saying, whenever you find a forward slash, get rid of it with nothing, replace it with nothing.
So, my first command is LS-EMVS, when I do LS-EMVS, I see a comma separated list of all my virtual environments.
And then I have two functions, three functions.
What is that?
Yes, a couple, there's four functions actually, because two of them are kind of the same.
So, one of them is MK Virtual Alps 2.
And that one is, if I wanted to use Virtual Alps, so the command I'm doing, and when I run that, if I write MK Virtual Alps 2, is Virtual Alps-P Python 2.
The dollar sign, work on home, slash, dollar sign, argv, semicolon, and source, dollar sign, work on home, slash, dollar sign argv, slash bin, slash activate.fish, semicolon, and echo,
virtual environment created in thumb codes.
So, what that is doing is I'm just writing a little function that says what I type in MK Virtual Alps 2, and then some text afterwards, I'm going to make a new virtual environment called that text with using Python 2 as the Python interpreter.
The only time I really use Python 2 nowadays is if I'm looking at some legacy code, or if I'm using Fabric, which is a wave, it's like a Python wrapper around SSH.
It's a good way of describing it.
So, I manage my Raspberry Pi's with Fabric, and so servers that I use all the time.
So, things like reboot, or update, or that kind of stuff, I just have some Fabric commands to do.
So, I can say all these things, all the same time, update, all these things, all the same time, reboot.
Anyway, so, usually I use Python 3, so I have one that's just called MK Virtual Alps.
I don't put a 3 after it because that's my normal one.
It's Virtual Alps.p, Python 3, and everything else about that is the same.
So, I'm still going to make a virtual Alps on Workup, Home, Slash, Dollar Sign, RGV, which is the argument that I'm entering,
and then sourcing the Activate.Fish file, and then the same virtual environment has been created.
So, now I have LSOMs to list all my virtual environments, MK Virtual Alps, or MK Virtual Alps 2 to make new ones,
and then once I make whatever I want to install, pick install-r, requirements.txt, if I already have a file that has all the things I want to install.
So, that's nice, and then my next one is RM Virtual Alps, which as it sounds like it's removed of a virtual environment.
So, in here, it's a little bit different, and this is how fish is different from Bash in the way it does tests.
And I'm not going to go into the details about how fish works with this, but I'll just show the command, and how Bash differs.
It's like a whole other thing. So, I'm going to avoid it for now.
But inside of there, I have if test-n, and then quotes, Dollar Sign, Virtual Alps, deactivate, end, and then RM-RF, work on Home, Slash, RGV.
Semicolon, and Echo, Virtual Environment, deleted.
So, what that is doing is saying if there is, if that virtual environment exists, then delete it.
Oh, if that virtual environment, if I am in that virtual environment right now, that's what the Dollar Sign, if test-n, in double quotes, Dollar Sign, Virtual Alps, that is a fish variable that says, you know, your current virtual environment that you're in.
And so, I'm saying, by saying, if test-n, I'm saying, if that exists, then deactivate.
So, if I'm in a virtual environment, deactivate it first, and then RM-RF, otherwise, it'll just skip that, and just remove it.
So, now I can list them, I can create them, but I don't have an easy way to get into one.
So, I use the similar command from Virtual Rapper, which is work-on, and so I made a function.
I wanted to do it in alias, but I decided to make a function out of it, because I didn't know if I was going to add more stuff to it later.
But I have it, so I probably could just make it in alias.
But my function called work-on is just source, Dollar Sign, work-on-home, slash Dollar Sign, argv, slash bin, so I have to activate fish, semicolon, and the word n, echo, switch to virtual environment.
And as it sounds like, I'm just sourcing that file.
So, if I make up, for instance, that fabric virtual environment, I'll say work-on-fabric, and then it'll switch to virtual environment, and you'll see that I'll be in the fabric virtual environment.
So, that's it. It's pretty simple. I really appreciate BJB's posts.
I don't want to go too far in the weeds with fish or with Python, but I find both of these things in my daily life just help me tremendously.
And I encourage other new committers and new submitters to Hacker Public Radio, and I hope BJB continues to submit, because I really like hearing what she has to say.
So, for now, that's it from Be Easy, and from here in Central Command, keep hacking.
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