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Regular Expression Problem

 
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# 8  
Old 04-01-2008
I got it. thanks
# 9  
Old 04-01-2008
You know, it would have helped if I had actually run your code instead of just reading it.

Your regex expects the line to begin with the date when it's always beginning with a open-square-bracket. ^_^

Also, you just put the filename at the end without redirecting it into the Perl one-liner.

Code:
 $ cat xyz.log 
[30/Dec/2008:12:03:07] info ( 816): CORE1116: Sun ONE Web Server 6.1SP5 B08/17/2005 22:09
[31/Dec/2008:12:03:08] info ( 817): CORE5076: Using [Java HotSpot(TM) Server VM, Version 1.5.0_11] from [Sun Microsystems Inc.]
[01/Jan/2008:12:03:08] info ( 817): WEB0100: Loading web module in virtual server [http-google] at [/abc]
[02/Jan/2008:12:03:08] info ( 817): WEB0100: Loading web module in virtual server [http-google] at [/abc]

 $ perl -MPOSIX -i -ne 'BEGIN{
 $d=strftime("%Y%m%d",localtime time-60*24*60*60);
 @m{qw(Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec)}=("01".."12")}
 print if m"^\[(\d+)/(\w+)/(\d{4})"&& "$3$m{$2}$1" gt $d' < xyz.log
[30/Dec/2008:12:03:07] info ( 816): CORE1116: Sun ONE Web Server 6.1SP5 B08/17/2005 22:09
[31/Dec/2008:12:03:08] info ( 817): CORE5076: Using [Java HotSpot(TM) Server VM, Version 1.5.0_11] from [Sun Microsystems Inc.]

ShawnMilo
# 10  
Old 04-01-2008
Thanks Shawn. Yea i came to know about those enclosing brackets earlier :--) []. But even if i am doing $d' xyz.log i do get the desired result. I am having a nightmare in using regex expression and regular expression but the more i come on the forums the more i learn :-).

Thanks for your assitance shawn.
# 11  
Old 04-01-2008
Quote:
Originally Posted by chris1234
Thanks Shawn. Yea i came to know about those enclosing brackets earlier :--) []. But even if i am doing $d' xyz.log i do get the desired result. I am having a nightmare in using regex expression and regular expression but the more i come on the forums the more i learn :-).

Thanks for your assitance shawn.
You can't go wrong with Mastering Regular Expressions by Jeffrey Friedl. The third edition came out recently. I highly recommend it. Glad I could help -- and it all came from that book. ;o)

Shawn
# 12  
Old 04-01-2008
Just ordered from Amazon.com. Hope to enjoy reading this book.
# 13  
Old 04-02-2008
Quote:
Originally Posted by chris1234
Just ordered from Amazon.com. Hope to enjoy reading this book.
That's fantastic! Friedl came up with an ingenious method for representing characters (including blank spaces) in print, which makes it very easy to learn. Once you cruise through the first 80 pages or so, you'll probably know more about regexes than most people.

After that, the book goes into some detail about how regex engines handle the expressions, and several sections detailing regex usage in specific languages, such as Perl and Java, which I didn't bother to read. Once you know the basics, you'll quickly become familiar with the little variations among the different languages which support them.

Then, like me, you will see a thread on this forum with "regular expression" in the subject and you'll eagerly jump in to help.

xkcd regex comic

Have fun!

Shawn
 
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