Question: For a very specific software application, we maintain a base of machines running fvwm 2.5. To update the menu structure, the fvwm2rc default config file is replaced during the update process performed by a package management system. To enable the new menu structure after an update, the user has to manually perform an action: Restart machine, re-login, restart fvwm. The preferred action is to choose "Window Manager > Restart Fvwm2" since no login is needed then and even the windows survive.

Question: How can I invoke an equivalent action as "Restart Fvwm2" from the command line or the package management system? The following command does not work (neither do similar ones):

```
fvwm -c "Restart"
[FVWM][SetupICCCM2]: <<ERROR>> another ICCCM 2.0 compliant WM is running, try -replace

```

"-replace" is no option since one needs to log in again after calling it.

Answer: 
`FvwmCommand` requires the `FvwmCommandS` FIFO to be open. If you cannot be sure all your users have one, it won't work.

But FVWM *will* restart on SIGUSR1.

An FVWM restart will even work if it is the last command in `.Xsession`.

But as other have said, if running under an X session manager (and FVWM has been compiled with session manager support), FVWM won't restart by itself, it will merely quit and expect to be restarted by the session manager. This will also affect SIGUSR1 behavior.
Another alternative is to use [FvwmCommand](http://www.fvwm.org/documentation/manpages/unstable/FvwmCommand.php):

```
$ FvwmCommand Restart

```