Shell Scripting - pipes and redirection

Question

I'm using CocoaDialog to present some feedback during execution of a download script. I wish to present an indeterminate progress bar whilst command operation us taking place. This is possible by piping text to CocoaDialog for the duration of the operation.

http://cocoadialog.sourceforge.net/documentation.html#progressbar_control

I thought I could do it using one command, as follows:

exec("curl -O $PATH_DOWNLOAD > $PATH_COCOADIALOG progressbar --indeterminate");

But this does not work.

Here's a more in-depth shell script that does it a different way:

http://cocoadialog.sourceforge.net/examples/progressbar.sh.txt

Any hints or tips appreciated.

Thanks,
matt

Answer 1

You can do without named pipe. popen/pclose you mentioned allows you to communicate with the process through anonymous one. Named pipes really necessary only when dealing with non-related (parent/child) processes.

Like so:

$pipe = popen("| nameOfTheExecuable"); write($pipe, "Something"); .... pclose($pipe);

$pipe is the handle you can use to write to the standard input of your sub-process.

Answer 2

This works:

curl -O $PATH_DOWNLOAD 2>&1 | $PATH_COCOADIALOG progressbar --indeterminate