Adds devnull file handle

helpers.go

@@ -538,7 +538,3 @@ func stringParensMatch(s string) bool {
 	return true
 }
 
-func GetFile(path string) *os.File {
-	devnull, _ := os.OpenFile(path, os.O_WRONLY, 0755)
-	return devnull
-}

lib.go

@@ -29,7 +29,12 @@ var stdLibrary = vars{
 	"stdin": &IOHandle{os.Stdin, true, "file (read-only)"},
 	"stdout": &IOHandle{os.Stdout, true, "file (write-only)"},
 	"stderr": &IOHandle{os.Stderr, true, "file (write-only)"},
-	"devnull": &IOHandle{GetFile(os.DevNull), true, "file (write-only)"},
+	"devnull": func() *IOHandle {
+		devnull, _ := os.OpenFile(os.DevNull, os.O_WRONLY, 0755)
+		dn := &IOHandle{devnull, true, "file (write-only)"}
+		openFiles = append(openFiles, dn)
+		return dn
+	}(),
 	// TODO add env pathlookup
 	"PI": number(math.Pi),
 	"E":  number(math.E),