path: root/2022/captions/emacsconf-2022-detached--getting-detached-from-emacs--niklas-eklund--main.vtt

WEBVTT captioned by anush

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Hello, everyone! Welcome to my talk,

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"Getting detached from Emacs".

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When I started to use Emacs,

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I quickly gravitated towards using it

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as much as I could.

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Magit, Org, Dired,

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a lot of new possibilities opened up.

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However, there was a workflow

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that was difficult for me to replace.

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The problem for me was running shell commands

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in sub-processes of Emacs,

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which in some situations led me to stick to

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using an external terminal.

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These situations,

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often revolved around long-running shell commands,

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either on my local machine

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or on a remote host.

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When I was on a remote host,

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I would also rely on using the program tmux

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to be able to detach from the remote process.

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My main concern at the time

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was that I didn't want to having to avoid

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restarting Emacs,

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because I needed to wait for a process to complete.

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However, there was of course a lot of things

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I was missing out on by not using Emacs.

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Therefore, my solution to resolving

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the issue of occasionally having to leave Emacs

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led me down the path of developing the package

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Detached.

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The package allows Emacs to delegate

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the responsibility of creating processes

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to the program dtach.

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It also makes sure to write

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the output of the process to a file,

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which we will see later on how that is being used.

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The package makes Emacs capable of

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attaching to these processes

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as well as managing them.

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In the package, each process is called a session,

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and inside of Emacs that is just

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an object with properties

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such as what command is being run,

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what working directory is used,

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where the output is stored, etc.

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The important aspect is also that

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these objects are being persistent,

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so they are stored over time.

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Today, I'm going to walk you through

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how I use the package and what advantages

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there are of treating processes like text.

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I'm going to start by opening up M-x shell,

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and I will run a command

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to update my package manager.

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Instead of pressing return,

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I'll simply press shift return

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to let Emacs delegate the execution

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to the dtach program.

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Emacs will immediately attach itself to the process,

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and we therefore don't perceive any difference

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from when running the command as a subprocess.

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We now have the option though

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to detach from the session,

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and later on we can of course

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reattach Emacs to the session.

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For me, this addresses the core

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of the problem that I had.

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But let’s see what’s more

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the new workflow inside of Emacs can bring.

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The package supports multiple user interfaces

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such as Eshell and Compile.

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I will therefore switch to the Detached project,

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and I will run the build command that I use.

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I will run it with detached-compile

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with the difference that

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I can detach from the compilation.

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One benefit of this new workflow is that

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I can get a system notification shown up here

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once a session has finished.

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Previously, I was either forced to have

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the terminal open so I could see it or hiding it,

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but then risking having forgotten it.

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How do we then see the output of a session?

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Get the detached-list-sessions command,

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and here we see

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the command that we just built,

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and we see the guix pull with an asterisk

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indicating that it is continuously running.

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If I press enter,

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we will get the output of the session here.

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And since it was run using compile,

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we also have compilation mode enabled here,

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so we could navigate between

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potential warnings or errors.

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And we see that there is a warning here.

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One thing that

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I have prepared here is that

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if I open up the user interface,

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we only see two sessions,

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but that is because we applied a filter here.

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So, we have actually the only sessions

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that are created within the last 12 hours

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and that are considered unique.

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So, if I remove the uniqueness,

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we also see that we have a previous build

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running on the main branch.

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So, I think that's typically normal

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that you might have that.

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And since the sessions can be considered text,

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we can just mark these two and check,

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does this warning exist on the main branch or not?

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So, we can just diff these ones

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and we see that the warning is only present

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on the emacsconf branch.

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Now, another benefit, in my opinion,

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of the new way of working is that

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I have these properties being displayed

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in the user interface.

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I can quickly see which commands are still running,

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what hosts they are running on,

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where they are running,

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and for how long they have been running.

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And if they have run,

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how long did it take?

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Occasionally, though, there might be

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even more input needed to distinguish sessions.

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So, what I typically do then is

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press A to annotate the session,

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I would add a "Warning found at emacsconf"

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And then it will show up this annotation

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in the echo area when I select the session.

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Another great improvement of using these sessions

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and consider them being text is,

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now we also see the guix pull completed here.

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Then we can also select and see that, okay,

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there is a lot of updates in this command,

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but let's not look at it now.

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Let's instead remember that

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previously last week

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when I ran a guix pull,

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I saw an Emacs package that looks interesting.

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I rather don't remember its full name,

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but it has something to do with collection.

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So, what I then can do is

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remove the 12 hour narrowing criteria,

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and we can see here I got sessions ranging back

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even to 28th of October.

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Since these are just to be considered text,

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I can--

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now let's first narrow the sessions

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to only show the ones that run guix pull.

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Then I would narrow based on the output

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containing a regular expression.

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So, I remember it was something with collection.

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And we got one hit.

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Here it should be something with collection.

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It was emacs-flymake-collection.

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This is something that is a

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very nice feature to have.

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It doesn't create any overhead

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of having these old sessions lying around

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and occasionally, it can be interesting

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to search through them as well.

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So, for me, this is another example of

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when bringing workflows into Emacs,

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it often opens up new exciting possibilities.

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Thanks a lot for listening.