diff --git a/perl/lib/NeedRestart/Interp/Perl.pm b/perl/lib/NeedRestart/Interp/Perl.pm
index 40aabb4..5031679 100644
--- a/perl/lib/NeedRestart/Interp/Perl.pm
+++ b/perl/lib/NeedRestart/Interp/Perl.pm
@@ -43,7 +43,7 @@ sub isa {
     my $pid = shift;
     my $bin = shift;
 
-    return 1 if($bin =~ m@/usr/(local/)?bin/perl@);
+    return 1 if($bin =~ m@^/usr/(local/)?bin/perl(5[.\d]*)?$@);
 
     return 0;
 }
diff --git a/perl/lib/NeedRestart/Interp/Python.pm b/perl/lib/NeedRestart/Interp/Python.pm
index 559666c..a30121d 100644
--- a/perl/lib/NeedRestart/Interp/Python.pm
+++ b/perl/lib/NeedRestart/Interp/Python.pm
@@ -42,7 +42,7 @@ sub isa {
     my $pid = shift;
     my $bin = shift;
 
-    return 1 if($bin =~ m@/usr/(local/)?bin/python@);
+    return 1 if($bin =~ m@^/usr/(local/)?bin/python([23][.\d]*)?$@);
 
     return 0;
 }
diff --git a/perl/lib/NeedRestart/Interp/Ruby.pm b/perl/lib/NeedRestart/Interp/Ruby.pm
index d02973d..72920f3 100644
--- a/perl/lib/NeedRestart/Interp/Ruby.pm
+++ b/perl/lib/NeedRestart/Interp/Ruby.pm
@@ -42,7 +42,7 @@ sub isa {
     my $pid = shift;
     my $bin = shift;
 
-    return 1 if($bin =~ m@/usr/(local/)?bin/ruby@);
+    return 1 if($bin =~ m@^/usr/(local/)?bin/ruby$@);
 
     return 0;
 }