# tmux
LinuxGSM uses [tmux](https://tmux.github.io) to run servers in the background so the server instance is not terminated when you close a terminal session.
{% hint style="info" %}
LinuxGSM requires *tmux => 1.6*
{% endhint %}
Tmux is a key component of LinuxGSM and replaced [screen](http://en.wikipedia.org/wiki/GNU_Screen) which was used on earlier versions. tmux has a few improvements over screen; mainly being better at handling standard Linux users, this was a major issue when developing with screen. tmux allows LinuxGSM to call up a game server running in the background so you can see what it is doing; this feature is available with [console](/commands/console.md) feature.
### tmuxception
Some server admins have attempted to run LinuxGSM within a `tmux` or `screen` session. As LinuxGSM calls tmux it is not possible to run LinuxGSM within a tmux or screen session.
## Known Issues
### Tmux 1.8
tmux 1.8 has an issue that prevents console logging from working. This is because the `pipe-pane` feature is broken in tmux 1.8 causing it not to output the console to the console log files. The only solution is to use another version of tmux.
{% hint style="warning" %}
tmux 1.8 is installed on CentOS 7 by default see guide below to installed a newer version
{% endhint %}
## create session failed: Operation not permitted
This issue normally occuires with CentOS and is caused by the standard user not having permissions to user *`/dev/ptmx`*.
```
create session failed: ./srcds_linux -game csgo: Operation not permitted
```
To fix this the user needs to be part of the `tty` group.
```
usermod -G tty csgoserver
```
To confirm the user has been added check *`/etc/group`*.
```
grep tty /etc/group
```
```
tty:x:5:csgoserver
```
## Upgrade tmux CentOS 7 using Ghettoforge
If the default version of tmux (1.8) installed on CentOS 7 it will fail to log the console output. To fix this it is possible to upgrade to a newer version of tmux using the [Ghettoforge](http://ghettoforge.org) repository.
Install Ghettoforge with the following command.
```
yum install http://mirror.ghettoforge.org/distributions/gf/gf-release-latest.gf.el7.noarch.rpm
```
Install tmux using the Ghettoforge repo.
```
yum --enablerepo=gf-plus install tmux
```
Once installed restart the server to complete the upgrade.
```
restart
```
---
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