# tmux

<figure><img src="https://1934041264-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LJf1_IiU2L1vVxT7iNe%2Fuploads%2FP2DGRMvNtZfvI983jh95%2Ftmux-logo-huge.png?alt=media&#x26;token=e087bebc-8841-4f27-b14c-efaeae239315" alt=""><figcaption></figcaption></figure>

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](https://docs.linuxgsm.com/commands/console) feature.

![LinuxGSM using tmux in console](https://1934041264-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LJf1_IiU2L1vVxT7iNe%2F-LWrQO6KP0vRNLi2hp_X%2F-LWrRBg414vWHZnzXdVY%2FXefICdv.png?alt=media\&token=7f72779d-4f7b-4e96-98ab-aca4083c83e2)

### 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.

![](https://1934041264-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LJf1_IiU2L1vVxT7iNe%2F-LWrQO6KP0vRNLi2hp_X%2F-LWrRhEmea-0ytcqyZhe%2Ftmuxception.png?alt=media\&token=e6b6da2c-316c-4d79-b50c-f5cab927e92c)

## 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
```