diff --git a/flags/common.go b/flags/common.go
index 2318b9d975..758e0a66cc 100644
--- a/flags/common.go
+++ b/flags/common.go
@@ -53,7 +53,7 @@ func (commonOpts *CommonOptions) InstallFlags(flags *pflag.FlagSet) {
 	}
 
 	flags.BoolVarP(&commonOpts.Debug, "debug", "D", false, "Enable debug mode")
-	flags.StringVarP(&commonOpts.LogLevel, "log-level", "l", "info", "Set the logging level")
+	flags.StringVarP(&commonOpts.LogLevel, "log-level", "l", "info", "Set the logging level (debug, info, warn, error, fatal)")
 	flags.BoolVar(&commonOpts.TLS, "tls", false, "Use TLS; implied by --tlsverify")
 	flags.BoolVar(&commonOpts.TLSVerify, FlagTLSVerify, dockerTLSVerify, "Use TLS and verify the remote")