Use the substitution operator s///g like this:

 1:30 >perl -wE "my $found = 'ENV{\"VCINSTALLDIR\"}\ATLMFC\LIB\amd64;E
+NV{\"LIBPATH\"}'; $found =~ s/ENV{\"(.*?)\"}/\$ENV(\"$1\")/g; say $fo
+und;"
$ENV("VCINSTALLDIR")\ATLMFC\LIB\amd64;$ENV("LIBPATH")

 1:30 >
[download]

Within the substitution, the parentheses capture the “value” text which is used in the replacement as $1. The /g modifier tells the regex engine to keep searching and substituting until the string is exhausted.

See perlretut and perlre.

Hope that helps,

Thank you!! Really I am weak in handling regex of this kind. Thank you soooo much

Also if you don't mind can you please explain me how exactly this command works

$found =~ s/ENV{\"(.*?)\"}/\$ENV(\"$1\")/g;

Thanks!!