diff --git a/context.go b/context.go
index 8f1dcd8..485f529 100644
--- a/context.go
+++ b/context.go
@@ -314,16 +314,14 @@ func checkRequiredFlags(flags []Flag, context *Context) requiredFlagsErr {
 	for _, f := range flags {
 		if rf, ok := f.(RequiredFlag); ok && rf.IsRequired() {
 			key := strings.Split(f.GetName(), ",")
-			shortName := strings.TrimSpace(key[0])
 			if len(key) > 1 {
 				// has short name
-				longName := strings.TrimSpace(key[1])
-				if !context.IsSet(shortName) && !context.IsSet(longName) {
+				if !context.IsSet(strings.TrimSpace(key[0])) && !context.IsSet(strings.TrimSpace(key[1])) {
 					missingFlags = append(missingFlags, key[0])
 				}
 			} else {
 				// does not have short name
-				if !context.IsSet(shortName) {
+				if !context.IsSet(strings.TrimSpace(key[0])) {
 					missingFlags = append(missingFlags, key[0])
 				}
 			}