my $s = 'variable chars anchor want this';

##</code><code>##

$s = 'anchor want this';

##</code><code>##

if( $s =~ m/^.*?(anchor.*)$/ ){ $s = $1; }

##</code><code>##

if( $s =~ m/^(.*?)anchor/ ){ my $bad = $1; $s =~ s/$bad//; }

##</code><code>##

$s =~ s/^.*?anchor/anchor/;

##</code><code>##

e.g., loops that utilize reverse, chop, split, ...