Perl正则表达式以匹配模式

Question

I am using nagios plugin(check_logs) to scan my logs and send alert, its a perl language based. i am trying to search the particular error from my log file but its not matching i dont know what mistake i am doing .

"POST /aimm/mweb/render.ps? HTTP/1.1" 500

The above string i want to match using regex

"POST \/aimm\/mweb\/render.ps? HTTP\/1.1" 500

The above string i have tried to match the pattern but its not working kindly guide me to solve this thread.

This is the exact nagios tag

{
                tag => "rplogcheck",
                type => 'rotating::uniform',
                logfile => "/opt/fundamo/apache/logs/nofile",
                rotation => "access[_\\d{4}\\-\\d{2}\\-\\d{2}]*.log",
                criticalpatterns => [
                '/"POST \/aimm\/mweb\/render\.ps\? HTTP\/1\.1" 500/'
],

options => 'noprotocol,sticky=300'
    }

);

its not showing any error but its not searching the exact pattern also , normal patterns i can match checked in nagios also the syntax seems correct.

still not able to figure what mistake i am doing in the pattern matching.

Answer 1

A question mark ? is a regex special character for matching repetition 1 or 0 times.

You need to escape it:

"POST \/aimm\/mweb\/render\.ps\? HTTP\/1\.1" 500

Additionally, a period . is also a regex special character and so should be escaped as well.

If you're trying to match a literal string in Perl, I would recommend using an alternative delimiter and quotemeta to avoid having to escape anything at all:

while (<DATA>) {
    print if m{\Q"POST /aimm/mweb/render.ps? HTTP/1.1" 500};
}

__DATA__
"POST /aimm/mweb/render.ps? HTTP/1.1" 500