in reply to
Re^2: regex not matching special char
in thread regex not matching special char
In addition to looking at the documentation linked by kennethk (and also at perlretut; see in particular the section titled 'Looking ahead and looking behind'), perhaps some insight as to the effect of the \b (and \B) zero-width word (and non-word) boundary assertions can be gained by split-ting one of the OPed example strings on each assertion:
>perl -wMstrict -le
"my $line2 = 'I:\$AVG\hello.log';
printf qq{'$_' } for split /\b/, $line2;
print qq{\n};
printf qq{'$_' } for split /\B/, $line2;
"
'I' ':\$' 'AVG' '\' 'hello' '.' 'log'
'I:' '\' '$A' 'V' 'G\h' 'e' 'l' 'l' 'o.l' 'o' 'g'
