---
name: "update"
section: "8"
platform: "linux"
package: "update"
version: "2.11-4"
release: "Debian 3.1 (Sarge)"
platforms: ["linux"]
url: "https://new.carta.tech/update/8"
---

# update(8)

periodically flush filesystem buffers.

## NAME

update - periodically flush filesystem buffers.

## SYNOPSIS

**update \[ options \]**

## DESCRIPTION

The **update** daemon flushes the filesystem buffers at a regular interval. It has two modes of operation. By default it will wake up every 5 seconds and flush some dirty buffers. Newer kernels do not need a user space update daemon.  This is automatically detected by **update** which will simply exit. The traditional behavior of waking up every 30 seconds to call [**sync**(2)](/sync/2.md) can be forced with an option if it is deemed necessary.

The following options are accepted by **update**:

- **-S, --use-sync**

  Use the traditional behavior of calling [**sync**(2)](/sync/2.md).

- **-s, --sync-interval** *secs*

  If using sync, wake up and call it every *secs* seconds. The default is every 30 seconds.

- **-f, --flush-interval** *secs*

  Unless using sync, wake up and flush some buffers every *secs* seconds. The default is every 5 seconds.

- **--help**

  Print a usage message on standard output and exit successfully.

- **--version**

  Print version information on standard output then exit successfully.

**update** should be started as early as possible during the boot process. If it is invoked by a non-privileged user, it calls sync and exits.

## SEE ALSO

[**init**(8)](/init/8.md), [**sync**(2)](/sync/2.md), [**sync**(8)](/sync/8.md)

## AUTHOR

Torsten Poulin \<torsten@diku.dk\>