使用正規表示式替換字串
s/foo/bar/; # replace "foo" with "bar" in $_
my $foo = "foo";
$foo =~ s/foo/bar/; # do the above on a different variable using the binding operator =~
s~ foo ~ bar ~; # using ~ as a delimiter
$foo = s/foo/bar/r; # non-destructive r flag: returns the replacement string without modifying the variable it's bound to
s/foo/bar/g; # replace all instances