Hi John,
Thanks for your advice.
(1) I actually have 'use warnings' enabled in the complete script.
'use strict' just gives me a load of unrelated compilation errors
like
"Global symbol "$INBOX" requires explicit package name at
./magic.pl line 8."
(2) I have also tried a WHILE loop but the result is the same
(3) the hex digits in the Request_Id all have A-F in lower case (so
there is only the range a-z)
However, it does no harm to put this in, just in case it changes in
the future. So I have made this change
(4) I tried [[:xdigit:]] but to no avail
So I remain stuck at square one !!
Regards,
Bill
-----Original Message-----
From: John W. Krahn [mailto:jwkr...@shaw.ca]
Sent: Monday, January 26, 2009 5:20 PM
To: Perl Beginners
Subject: Re: Simple regex problem has me baffled
Bill Harpley wrote:
> Hello,
Hello,
> I have simple regex problem that is driving me crazy.
>
> I am writing a script to analyse a log file. It contains Java related
> information about requests and responses.
>
> Each pair of Request (REQ) and Response (RES) calls have a unique
> Request ID. This is a 5 digit hex number contained in square brackets
> (e.g. "[81c2d]" ).
>
> Using timestamps in each log entry, I need to calculate the time
> difference between the start of the Request and the end of the
Response.
>
> As a first step, I thought I would identify the matching REQ/RES pairs
> in the log and then set about extracting the timestamp information and
> doing the calculations.
>
> I started with a simple script to extract the Request IDs from each
> log entry. Here is what one looks like (names have been changed to
> protect the innocent).
>
>
> [2009-01-23 09:20:48,719]TRACE [server-1] [http-80-5]
> a...@mydomain.net
> :090123-092048567:f5825 (SetCallForwardStatusImpl.java:call:54) -
> RequestId [81e80] SetCallForwardStatus.REQ { accountNumber:=W12345,
> phoneNumber:=12121212121, onBusyStatus:=true, busyCurrent:=voicemail,
> onNoAnswerStatus:=false, noAnswerCurent:=voicemail,
> onUncondStatus:=false, uncondCurrent:=voicemail }
>
> So I need to extract the 5 hex digits in "RequestId [81e80]". Sounds
> simple, eh?
>
> Here is a fragment of my initial script:
You should have the warnings and strict pragmas at the beginning of your
program to let perl help you find mistakes:
use warnings;
use strict;
> open ( DATA, "< $INBOX/sample.log") || die "Cannot open source file:
> $!";
> open ( FILE, "> $INBOX/request.dat") || die "Cannot open request file:
> $!";
>
> chomp(@list=<DATA>);
>
> foreach $entry(@list)
> {
It looks like you don't really have to read the entire file into memory
in order to process it. You should perhaps use a while loop instead
which will only read one line at a time:
while ( my $entry = <DATA> ) {
chomp $entry;
And you may not need to chomp the current line if you are not accessing
the data at the end of the line.
> $entry =~ /\[([a-z0-9]{5})\]/;
You are looking for hexadecimal digits so you want either [a-fA-F0-9] or
[[:xdigit:]] instead.
> print "$1\n"; # print to screen
The contents of $1 are only valid if the regular expression matched
successfully, otherwise $1 retains the contents from the previously
successful match.
if ( $entry =~ /RequestId\s+\[([a-fA-F0-9]{5})\]/ ) {
print "$1\n";
}
> # print FILE "$1\n"; # print to file
> }
John
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annoyance to those of us who do. -- Isaac Asimov
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