[Lazarus] Run 3 extrenal program, pipeline

[Sven Barth]

Am 02.02.2012 12:00, schrieb xmldom at seznam.cz:
> Hi, I need run 3 external program and redirected output: first | second | third
>
> For example:
>     df -hT | grep -v -E 'tmpfs|ecryptfs' | grep 'sda2'
> it gives
>     /dev/sda2     ext4     19G   11G  7,6G  58% /
>
> I use this http://wiki.lazarus.freepascal.org/Executing_External_Programs#How_to_redirect_output_with_TProcess sample code. It works fine for  first | second.

Completely different solution: Why do you need to run three processes at 
all? Just get the output of "df -hT" and then search the corresponding 
strings using a for loop...

e.g.

function GetDFOfSda2: String;
var
   slist: TStringList;
   s: String;
begin
   slist := TStringList.Create;
   try
     GetOutputOfProcess('df', ['-hT'], slist); // hypothetic function 
that returns the output of a process in a TStringList
     for s in slist do begin
       if (Pos('tmpfs', s) = 0) and (Pos('ecryptfs', s) = 0) then
         Continue;
       if Pos('sda2', s) > 0 then
         Exit(s);
     end;
   finally
     slist.Free;
   end;
end.

Of course this can be improved by using regular expressions and setting 
the drive to look for through a parameter, but it should show you the 
basic concept. :)

Regards,
Sven