---
author: James
date: 2018-11-07 07:40:45+00:00
medium_post:
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post_meta:
- date
tags:
- linux
- script
- tmux
- Open Source
title: Why is Tmux crashing on start?
type: posts
url: /2018/11/07/why-is-tmux-crashing-on-start/
---

I spent several hours trying to get to the bottom of why tmux was crashing as soon as I ran it on Fedora. It turns out there’s a simple fix. When tmux starts it uses /dev/ptmx to create a new TTY (virtual terminal) that the user can interact with. If your user does not have permission to access this device then tmux will silently die. A good way to verify this is to try running [screen][1] too.

In my case I realised that my user was not a member of the user group “tty” on my system. The answer was therefore simple:

<pre>sudo usermod -a -G tty james</pre>

I hope this helps someone avoid spending hours searching for the right incantation.

 [1]: https://en.wikipedia.org/wiki/GNU_Screen