[Gambas-user] Obtaining Sound Output Monitor's Name

[Tobias Boege]

On Tue, 10 Dec 2013, John Rose wrote:
> I'm trying to obtain the sound output monitor's name (as a string using 
> the Shell command) for later use in an Exec command (calling ffmpeg).
> 
> Running  the appropriate command in a Terminal gives:
>    john at ...2811...:~$ pactl list | grep -A2 '^Source #' | grep 'Name: 
> .*\.monitor$' | awk '{print $NF}' | tail -n1
>    alsa_output.pci-0000_00_1b.0.analog-stereo.monitor
> 
> I have Gambas code for opening FMain form as:
>    Dim sSoundMonitorExtractor As String
>    Me.Center()
>    sSoundMonitorExtractor = Shell$("pactl list | grep -A2 '^Source #' | 
> grep 'Name: .*\\.monitor$' | awk '{print $NF}' | tail -n1")
>    Shell sSoundMonitorExtractor To sSoundMonitor
>    Print "Sound Monitor = " & sSoundMonitor
> 
> I have 2 backslashes in the Shell$'s string as otherwise the compiler 
> objects. When I run the Gambas executable, the Console displays:
>    Sound Monitor =
> I.e. sSoundMonitor is not set. What am I doing wrong?
> 

Shell$() is there to quote arguments, not entire commands. Just look at

$ gbx3 -e 'Shell$("pactl list")'
pactl\ list

so you will execute "pactl\ list" which will be interpreted by the shell as
a program named "pactl list" which is *not* the program "pactl", called with
argument "list". Shell$() is there to sanitise user input. Leave it away and
it should work (so far).

Regards,
Tobi