executeCommandLine - Type mismatch: type void is not applicable at this location

I’m running OH 4.1.0 in a docker environment.

I have the following test rule:
rule “Dateiinhalt an Telegram senden”

    Item Switch_Admin_Test received update // Schalter 'Switch_Admin_Test' betätigt wird
    val filePath = "/openhab/conf/import/Losungen_2023.txt"  // Pfad zur Datei
    val message = executeCommandLine("cat "+ filePath) // Dateiinhalt auslesen

    // Überprüfen, ob der Dateiinhalt erfolgreich ausgelesen wurde
    if (message !== null && message.trim() !== "") {
        telegramAction.sendTelegram("Dateiinhalt: " + message) // Telegram-Nachricht senden
    } else {
        logError("Rule", "Fehler beim Auslesen der Datei.") // Fehlermeldung, falls das Auslesen fehlschlägt

VisualCode shows me the following Messag:
"Type mismatch: type void is not applicable at this location"

In the log I get:
java.io.IOException: Cannot run program "cat /openhab/conf/import/Losungen_2023.txt": error=2, No such file or directory

yes, the file exists.
Within the container there is no prob for this “command line”.

What is the issue here?

Please review the docs for executeCommandLine. Actions | openHAB

In particular:

executeCommandLine(String commandLine) : Executes a command on the command line without waiting for the command to complete.

If it doesn’t wait, it obviously cannot return the result of the command.

executeCommandLine(Duration.ofSeconds(timeout), String commandLine) : Executes a command on the command and waits timeout seconds for the command to complete, returning the output from the command as a String.

Without a timeout, executeCommandLine doesn’t return anything (i.e. void).

Be careful with that. When you run something manually inside the container you are running as user root. However, openHAB is running as some other user (uid 1000 by default). You have to be careful about user permissions when testing commands like that by using su openhab or su 1000 first. sudo does not exist in the container.

1 Like

THX, die syntax war falsch
So funktioniert sie:
val message = executeCommandLine(Duration.ofSeconds(1), "cat", "Pfad zur Datei")