$str = q{ Ab._@c,D. -!'ÿ_g1-}; 
  
$str =~ s/\s/_/g;      # replace whitespace with underscore 
$str =~ s/[^\w-]+//g;  # eliminate illegal characters 
$str =~ s/^[-_]+//;    # strip leading dashes/underscores 
$str =~ s/[-_]+$//;    # strip trailing dashes/underscores 
$str = lc $str;        # make the string lowercase

s$$ab21b8d15c3d97bd6317286d$;$"=547269736;split'i',join$,,map{chr(($*+= 
($">>=1)&1?-hex:hex)+0140)}/./g;$"=chr$";s;.;\u$&;for@_[0,2];print"@_,"

# Lowercase 
$string = lc $string; 
# Get rid of unwanted chars 
$string =~ tr/a-z0-9_- //c; 
# Remove leading and trailing Whitespace 
$string =~ s/^\w*(.*?)\w*$/$1/; 
# Replace remaining whitespace with underscores 
$string =~ tr/ /_/; 
# Check the last and first character 
$string =~ s/^[^a-z0-9]*(.*?)[^a-z0-9]*/$1/;