It's also possible to use nested substitutions (I've use single-quotes instead of double-quotes to avoid the WinNoyance® of escaping a bunch of "s):

>perl -wMstrict -le
"for my $str (@ARGV) {
   print $str;
   $str =~ s{ (' [^']* ') }
            { (my $x = $1) =~ s{ [^'/] }{x}xmsg;  $x
            }xmsge;
   print $str;
   }
"
file='path/goes/here'  foo'a/b/c'bar  '///'  'a/b/c'
file1='aa/bb/cc',file2='/dd/'
file='path/goes/here'
file='xxxx/xxxx/xxxx'
foo'a/b/c'bar
foo'x/x/x'bar
'///'
'///'
'a/b/c'
'x/x/x'
file1='aa/bb/cc',file2='/dd/'
file1='xx/xx/xx',file2='/xx/'
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