Re: Losing first entry of Apache log

I would guess that in the for loop when you call <LOGFILE>; it grabs a line, and then grabs a new line in the while loop.

for ($logpos = tell(LOGFILE); <LOGFILE>; . . .#here
  while (<LOGFILE>) { #and here
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So everytime it hits the inside for loop it grabs two lines before it prints one (and only prints the latter). There is File::Tail for this sort of thing though.

-enlil

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Re: Re: Losing first entry of Apache log by Grygonos (Chaplain) on Feb 25, 2004 at 18:11 UTC
I was testing that theory and it is in fact what is happening. The modified code below works and does not drop the first entry... also a bit easier to read. I would reccomend using while(1) for continous loops. `#!/usr/bin/perl -w use strict; my $LogFile="C:/test.txt"; my $naptime=3; my $logpos; #Reads LOGFILE continuously open(LOGFILE,"<$LogFile") \|\| die "Couldn't open file Status - $!\n"; while (1) { sleep $naptime; $logpos = tell(LOGFILE); while(<LOGFILE>) { print; } seek(LOGFILE, $logpos, 0); # seek to last known }` [download] `<edit>`the more I thought about it you don't even need the `$logpos` variable. Just use `seek(LOGFILE,0,0)` to seek to the beginning,since it seemed like what you wanted to do. Although if you have a specific point in the file you want to start reading from then you will need to predefine it and even then you still wouldn't need the call to `tell(LOGFILE)` I believe`</edit>` Hope this helps. Grygonos	[reply] [d/l] [select]

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Re: Re: Losing first entry of Apache log
by Grygonos (Chaplain) on Feb 25, 2004 at 18:11 UTC

I was testing that theory and it is in fact what is happening. The modified code below works and does not drop the first entry... also a bit easier to read. I would reccomend using while(1) for continous loops.

#!/usr/bin/perl -w

use strict;

my $LogFile="C:/test.txt";

my $naptime=3;
my $logpos;
#Reads LOGFILE continuously
open(LOGFILE,"<$LogFile") ||  die "Couldn't open file Status - $!\n";
while (1) 
{
    sleep $naptime;

    $logpos = tell(LOGFILE);
    
    while(<LOGFILE>)
    {
        print;
    }

    seek(LOGFILE, $logpos, 0);  # seek to last known 
 }
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<edit>the more I thought about it you don't even need the $logpos variable. Just use seek(LOGFILE,0,0) to seek to the beginning,since it seemed like what you wanted to do. Although if you have a specific point in the file you want to start reading from then you will need to predefine it and even then you still wouldn't need the call to tell(LOGFILE) I believe</edit>

Grygonos

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