Re: Reading a file as it fills up by another program
Re: Reading a file as it fills up by another program
- Subject: Re: Reading a file as it fills up by another program
- From: Harald E Brandt <email@hidden>
- Date: Fri, 12 Dec 2003 15:04:30 +0100
+--> Christopher Stone wrote 03-12-12:
At 16:47 +0100 12/11/2003, Harald E Brandt wrought:
How to read a file, record by record, as the file is being filled
up by another process?
...
If using 'open for access', EOF will retain its value of 0 until
the file is closed, so it won't read the file as it fills up. Is it
possible at all to use the standard 'read' to do that?
______________________________________________________________________
Hello Harald,
Hmm. There is never any need to open a file if you just want to read it.
Does your Unix process keep the file open? Or does it close it
after it writes to it?
+-
It keeps the file open - it is a redirect (incl stderr) after a pipe.
I just talked to a Unix guru who sais that this is a relatively
common problem caused by the fact that Unix usually buffers
everything before it is actually written to file. That means I am
stuck!
TN 2065 (
http://developer.apple.com/technotes/tn2002/tn2065.html)
states (concerning "How do I read the results as they come in?"):
"What you can do, however, is to put the command into the background
(see the next question), send its output to a file, and then read the
file as it fills up".
So that's what I am doing! But if the thing gets buffered, no tool
whatsoever will be able to read the file because the file is actually
not written to until the whole thing is over!! The size of the file
is only about 2 kB, but it may take anything from a few seconds to a
few minutes to fill it up. I just checked by simply doing 'ls -l'
repeatadly, and indeed, the file has zero length until the original
process (a curl download) terminates!
I really wonder if Chris himself has tried the suggestion in TN 2065?.
Is it really *impossible* to get those progress reports from curl and
similar programs into AppleScript Studio so I can show them in the
GUI (without waiting for the whole thing to terminate)?
Hoping for the gurus to answer...
--heb
_______________________________________________
applescript-users mailing list | email@hidden
Help/Unsubscribe/Archives:
http://www.lists.apple.com/mailman/listinfo/applescript-users
Do not post admin requests to the list. They will be ignored.