use strict;
my $str = '[2019-01-15 13:44:43,432] [[ACTIVE] ExecuteThread: \'45\' for queue: \'weblogic.kernel.Default (self-tuning)\'] WARN SiemLogger - {"EVENT_NAME":"SIEM","EVENT_ID":"LOGOUT","User_Id":"ROBKNT1810","X_Corelation_ID":"null","Client_IPAddress":"null","Acting_As_ID":"null","Message":"MobileSignOutPage - User successfully logged out."}
';
my $regex = qr/.*?{"EVENT_NAME":"(?<tag6>[^"]*)","EVENT_ID":"(?<action>[^"]*)","User_Id":"(?<login>[^"]*)","X_Corelation_ID":"(?<policy>[^"]*)","Client_IPAddress":"(?<sip>[^"]*)","Acting_As_ID":"(?<account>[^"]*)","Message":"(?<tag2>[^"]*)"}/mp;
if ( $str =~ /$regex/g ) {
print "Whole match is ${^MATCH} and its start/end positions can be obtained via \$-[0] and \$+[0]\n";
# print "Capture Group 1 is $1 and its start/end positions can be obtained via \$-[1] and \$+[1]\n";
# print "Capture Group 2 is $2 ... and so on\n";
}
# ${^POSTMATCH} and ${^PREMATCH} are also available with the use of '/p'
# Named capture groups can be called via $+{name}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html