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System Application Support Libraries (SASL)
Reference Manual
Version 2.3.4

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# rel

### FILE

rel

### FILE SUMMARY

Release resource file

### DESCRIPTION

The release resource file specifies which applications are 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 should 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() is the name of the release.

- Vsn = string() is the version of the release.

- EVsn = string() is the version of ERTS the release is intended for.

- Application = atom() is the name of an application included in the release.

- AppVsn = string() is the version of an application included in the release.

- Type = permanent | transient | temporary | load | none is the start type of an application included in the release.

  If Type = permanent | transient | temporary, the application will be loaded and started in the corresponding way, see application(3). If Type = load, the application will only be loaded. If Type = none, the application will be neither loaded nor started, although the code for its modules will be loaded. Defaults to permanent

- IncApps = [atom()] is 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(3), relup(4), systools(3)