Re: using a variable to help define a regular expression

On Thu, 13 Mar 2008 07:49:28 +0000, tbh wrote:

> <schuler.steffen@[EMAIL PROTECTED]
> wrote in message
> news:f47cefc3-0878-4476-8d0a-
e81678a8e50f@[EMAIL PROTECTED]
>> Faster than using a dynamic string as a regex is to use a regex
>> constant (e.g. /.../).
> 
> thanks. is that possible though, when i need to put a variable part in
> the middle of my regex (constant for each run, but variable in general)?
> 
>> E.g.:
>> 
>> unpackHourlyWebLogs.bash  11 |
>> {
>>   base=f30
>>   gawk 'tolower($5) ~ /^\/'"$base"'\// {
                         ^^^^^^^^^^^^^^^^
this is the use of a regex constant with embedded shell variable

>>           print $3, $5, $6
>>           if (++i == 10) exit
             ^^^^^^^^^^^^^^^^^^^
this line does the head; you can remove it

>>         }'
>> }

>> And still faster than your pipe from gawk to head is to let gawk do the
>> head cmd.
> 
> thanks, good to remember. head is not part of the actual assignment here
> -- just there to reduce the data storm for the test.
> 
> cheers,
> 
> Tim





-- 
Steffen