Understanding with this regex in Perl without assigment -

Understanding with this regex in Perl without assigment -

can explain me how understand part of code code extracted pflogsumm.pl log analyzer postfix mail

while(<>) { next if(defined($datestr) && ! /^$datestr/o); s/: \[id \d+ [^\]]+\] /: /o; # lose "[id nnnnnn some.thing]" stuff $logrmdr; more code }

i can't undestand regex doing because don't have assigment, don't have conditional, simple there

thanks

by default, regular expressions (and many other functions) operate on $_.

s/: \[id \d+ [^\]]+\] /: /o;

is equivalent to:

$_ =~ s/: \[id \d+ [^\]]+\] /: /o;

this replaces : [id number ...] : in input line.

this mutual idiom should see in many perl scripts, should used it.

regex perl