Is there a Perl-compatible regular expression to trim whitespace from both sides of a string?

Question

Is there a way to do this in one line?

$x =~ s/^\\s+//;
$x =~ s/\\s+$//;

In other words, remove all leading and trailing whitespace from a stri

Answer 1

In zsh with PCRE mode active:

function trim() {
    local out="$*"
    [[ "$out" =~ '^\s*(.*\S)\s*$' ]] && out="$match[1]" || out=''
    print -nr -- "$out"
}