sezaru
I have a mix task that does some stuff, and in the end it created a shell command that I want to run. The command can be something that willl require full IO support, so you can something like a psql session, an ssh session, etc.
Is there some way to run that command before/after exiting the Elixir task/beam so it is executed as a normal command in bash?
If not, is there some way that I can run that command inside the beam, but the beam give full IO handling to the process until it finishes?
Trying to doing something like this with System.cmd doesn’t seem to do the trick.
Where Next?
Trending in Questions
Other Trending Topics
Latest on Elixir Forum
Sponsor Spotlight
Practical resources that improve the lives of professional developers.
Categories:
Sub Categories:
Forums
Popular Tags
- #ecto
- #liveview
- #troubleshooting
- #learning-elixir
- #library
- #deployment
- #erlang
- #testing
- #genserver
- #mix
- #absinthe
- #remote-other
- #otp
- #plug
- #how-to-question
- #macros
- #postgres
- #elixirconf
- #channels
- #exunit
- #discussion
- #code-sync
- #podcasts
- #javascript
- #onsite
- #dialyzer
- #docker
- #authentication
- #umbrella
- #full-time-contract
- #podcasts-by-brainlid
- #ecto-query
- #ai
- #elixirconf-us
- #blog-post
- #elixir-ls
- #phoenix_html
- #iex
- #graphql
- #genstage
- #websockets
- #supervisor
- #advent-of-code
- #distillery
- #processes
- #api
- #forms
- #elixirconf-eu
- #metaprogramming
- #hex
Our Sponsors
Build Elixir applications with speed and confidence.
Supporting innovation across the BEAM ecosystem.
We build reliable cloud platforms for business-critical systems.
Error tracking, logs, uptime, and Just Enough APM. Built for developers.
Elixir, Erlang & BEAM conferences from Code Sync - join us in 2026!
Practical resources that improve the lives of professional developers.
Master modern tools, write cleaner code, and tackle real-world challenges.
The deployment platform built for Elixir: PaaS ease, VPS control.
The team behind Membrane, Popcorn, LiveDebugger. Available for hire.
Courses that'll move you from confusion to "Aha, now I get it!"
Showing Posts 1 to 8- Show Best Posts
- Show All (oldest first)
- Show All (newest first)
camatcode
Would Porcelain.shell/2 or Porcelain.exec/3 help you?
sezaru
Thanks for the suggestion, but it doesn’t seem to work from my tests, it will still not give the keyboard IO control to the external program/shell
Hermanverschooten
I used to have an issue with running a system command that needed te be independent of the Beam, I wrote a nif to handle this, don’t know if it will help you. It’s on hex.
I must say it’s been years since I have used it. The project it was for has been archived.
sezaru
Hey @Hermanverschooten , I just tried it but unfortunately it doesn’t give the process access to the terminal input.
Here is what I did as an example:
This will create an ssh session to a server I have in Fly and halt the beam. Since the process is outside the beam, it does keep running, but then it will give me the following error because it can’t access the input/output:
VictorGaiva
Why don’t you do the oposite? Call an Elixir Script from a Bash Script, and when it exits you can do anything.
You could even get the exit codes to do some logic.
sezaru
Because I want to have these as mix tasks, I don’t think I can call bash directly from a mix task AFAIK
Hermanverschooten
I don’t remember the code it is too long ago I wrote it.
But what comes to mind is if you could pass along the current file descriptors for input and output to the new process or could be you need to start a pty.
gtcode
I made good use of
erlexecinclaude_code_sdk_elixir:https://github.com/nshkrdotcom/claude_code_sdk_elixir/blob/9e0d697880b01184abbe5fc2c23a7fa2fb9f2f72/mix.exs#L33
(repo is on an exploratory journey on the main branch currently, apologies)