in reply to Removing Non-Ascii chars from text file
$str =~ s/[^!-~\s]//g;
In the above, !-~ is a range which matches all characters between ! and ~. The range is set between ! and ~ because these are the first and last characters in the ASCII table (Alt+033 for ! and Alt+126 for ~ in Windows). As this range does not include whitespace, \s is separately included. \t simply represents a tab character. \s is similar to \t but the metacharacter \s is a shorthand for a whole character class that matches any whitespace character. This includes space, tab, newline and carriage return.
Or simply, $str !~ s/[^[:ascii:]]//g;