---
name: "rel"
section: "5"
platform: "linux"
package: "erlang-manpages"
version: "1:25.2.3+dfsg-1+deb12u4"
release: "Debian 12 (Bookworm)"
platforms: ["linux"]
url: "https://new.carta.tech/rel"
---

# rel(5)

Release resource file

## NAME

rel - Release resource file

## DESCRIPTION

The *release resource file* specifies which applications are included in a release (system) based on Erlang/OTP.

This file is used by the functions in *systools* when generating start scripts (*.script*, *.boot*) and release upgrade files (*relup*).

## FILE SYNTAX

The release resource file is to be called *Name.rel*.

The *.rel* file contains one single Erlang term, which is called a *release specification*. The file has the following syntax:

```
{release, {RelName,Vsn}, {erts, EVsn},
  [{Application, AppVsn} |
   {Application, AppVsn, Type} |
   {Application, AppVsn, IncApps} |
   {Application, AppVsn, Type, IncApps}]}.
```

- ***RelName = string()*:**

  Release name.

- ***Vsn = string()*:**

  Release version.

- ***EVsn = string()*:**

  ERTS version the release is intended for.

- ***Application = atom()*:**

  Name of an application included in the release.

- ***AppVsn = string()*:**

  Version of an application included in the release.

- ***Type = permanent \| transient \| temporary \| load \| none*:**

  Start type of an application included in the release.

  If *Type = permanent \| transient \| temporary*, the application is loaded and started in the corresponding way, see *[application(3erl)](/application/3erl.md)*.

  If *Type = load*, the application is only loaded.

  If *Type = none*, the application is not loaded and not started, although the code for its modules is loaded.

  Defaults to *permanent*

- ***IncApps = \[atom()\]*:**

  A list of applications that are included by an application included in the release. The list must be a subset of the included applications specified in the application resource file (*Application.app*) and overrides this value. Defaults to the same value as in the application resource file.

**Note:**

The list of applications must contain the Kernel and STDLIB applications.

## SEE ALSO

*[application(3erl)](/application/3erl.md)*, *[relup(5)](/relup/5.md)*, *[systools(3erl)](/systools/3erl.md)*