> -----Original Message-----
> From: Tyler Longren [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, August 15, 2001 10:13 AM
> To: Perl-Beginners
> Subject: status messages as the program progresses
>
>
> Hello everyone,
>
> I have a while loop that loops through a text file for quite
> a while (10
> min or so). Is there any way to print a status-type message
> while it's
> looping through?
> I did something like this now:
>
> my $i=0;
> while ($i le "10000000") {
> print "Processing\r";
> }
I hope that's not the whole script, since $i doesn't change :)
>
> And that works, but if I run the script like this:
> ./script.pl > test.txt
>
> I get a BUNCH of "Processing" lines in test.txt. Is there
> any other way I
> can do this?
One thing you can do is print the message every so many lines.
my $i = 0;
while (<>)
{
# (...process line here...)
print "$i lines processed\n" unless ++$i % 100;
}
This will print:
100 lines processed
200 lines processed
300 lines processed
and so on.
Or, you can print the message every so many seconds:
my $last_time = time;
my $i = 0;
while (<>)
{
# (...process line here...)
$i++;
print("$i lines processed\n"), $last_time = time if time - $last_time
> 30;
}
This uses the variable $last_time to keep track of when a message was last
printed. If this has been more than 30 seconds, a line is printed and the
$last_time variable is updated.
These methods assume each iteration of the loop is relatively quick. If the
processing for a single line can be lengthy, you can use a $SIG{ALRM}
handler
to cause an interrupt in the middle of processing. However, it's generally
not a good idea to do I/O during an event handler, so you usually set a flag
that you check somewhere inside your processing loop.
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