All you should have to do is have each program read from stdin & write
to stdout. I've done it before. There is no reason to write it in
Lazarus at all, just use FreePascal. If you are trying to execute this
all from a tprocess, be aware that this in't bash. I would put it in a
script and try it there.
On 02/02/2012 06:00 AM, [email protected] wrote:
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.
For three programs I try edit it:
function threePipe(inputA, inputB, inputC: string): string;
var
FirstProcess, SecondProcess, ThirdProcess: TProcess;
Buffer: array[0..127] of char;
ReadCount: Integer;
ReadSize: Integer;
begin
FirstProcess := TProcess.Create(nil);
SecondProcess := TProcess.Create(nil);
ThirdProcess := TProcess.Create(nil);
FirstProcess.Options := [poUsePipes];
SecondProcess.Options := [poUsePipes];
ThirdProcess.Options := [poUsePipes,poStderrToOutPut];
FirstProcess.CommandLine := inputA;
SecondProcess.CommandLine := inputB;
ThirdProcess.CommandLine := inputC;
FirstProcess.Execute;
SecondProcess.Execute;
ThirdProcess.Execute;
while FirstProcess.Running or (FirstProcess.Output.NumBytesAvailable> 0) do
begin
if FirstProcess.Output.NumBytesAvailable> 0 then
begin
ReadSize := FirstProcess.Output.NumBytesAvailable;
if ReadSize> SizeOf(Buffer) then
ReadSize := SizeOf(Buffer);
ReadCount := FirstProcess.Output.Read(Buffer[0], ReadSize);
SecondProcess.Input.Write(Buffer[0], ReadCount);
end;
end;
SecondProcess.CloseInput;
while SecondProcess.Running or (SecondProcess.Output.NumBytesAvailable> 0) do
begin
if SecondProcess.Output.NumBytesAvailable> 0 then
begin
ReadSize := SecondProcess.Output.NumBytesAvailable;
if ReadSize> SizeOf(Buffer) then
ReadSize := SizeOf(Buffer);
ReadCount := SecondProcess.Output.Read(Buffer[0], ReadSize);
ThirdProcess.Input.Write(Buffer[0], ReadCount);
end;
end;
ThirdProcess.CloseInput;
while ThirdProcess.Running do
Sleep(1);
ReadSize := ThirdProcess.Output.NumBytesAvailable;
if ReadSize> SizeOf(Buffer) then
ReadSize := SizeOf(Buffer);
if ReadSize> 0 then
begin
ReadCount := ThirdProcess.Output.Read(Buffer, ReadSize);
//WriteLn(Copy(Buffer,0, ReadCount));
end
else
WriteLn('grep did not find what we searched for. ',
ThirdProcess.ExitStatus);
FirstProcess.Free;
SecondProcess.Free;
ThirdProcess.Free;
threePipe := Copy(Buffer,0, ReadCount);
end;
But after i call
Label1.Caption:=threePipe('df -hT', 'grep -v -E ''tmpfs|ecryptfs''', 'grep
''sda2''');
function my application end with infinite loop.
Where I do an error?
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