diff --git a/cmd/analyze.go b/cmd/analyze.go
index 20c7050..06f50bd 100644
--- a/cmd/analyze.go
+++ b/cmd/analyze.go
@@ -148,4 +148,5 @@ func init() {
 	analyzeCmd.Flags().StringSliceVarP(&opt.Regions, "region", "r", []string{}, "target region")
 	analyzeCmd.Flags().BoolVarP(&opt.AllAccounts, "all-accounts", "A", false, "all accounts")
 	analyzeCmd.Flags().BoolVarP(&opt.AllRegions, "all-regions", "R", false, "all regions")
+	analyzeCmd.Flags().StringVarP(&opt.LogFilePrefix, "log-file-prefix", "p", "", "log file prefix")
 }
diff --git a/cmd/events.go b/cmd/events.go
index a42f8db..671f5a6 100644
--- a/cmd/events.go
+++ b/cmd/events.go
@@ -64,4 +64,5 @@ func init() {
 	eventsCmd.Flags().StringSliceVarP(&opt.Regions, "region", "r", []string{}, "target region")
 	eventsCmd.Flags().BoolVarP(&opt.AllAccounts, "all-accounts", "A", false, "all accounts")
 	eventsCmd.Flags().BoolVarP(&opt.AllRegions, "all-regions", "R", false, "all regions")
+	eventsCmd.Flags().StringVarP(&opt.LogFilePrefix, "log-file-prefix", "p", "", "log file prefix")
 }
diff --git a/cmd/size.go b/cmd/size.go
index 17698e8..a3a3497 100644
--- a/cmd/size.go
+++ b/cmd/size.go
@@ -125,4 +125,5 @@ func init() {
 	sizeCmd.Flags().StringSliceVarP(&opt.Regions, "region", "r", []string{}, "target region")
 	sizeCmd.Flags().BoolVarP(&opt.AllAccounts, "all-accounts", "A", false, "all accounts")
 	sizeCmd.Flags().BoolVarP(&opt.AllRegions, "all-regions", "R", false, "all regions")
+	sizeCmd.Flags().StringVarP(&opt.LogFilePrefix, "log-file-prefix", "p", "", "log file prefix")
 }
diff --git a/trail/trail.go b/trail/trail.go
index 8ce1172..7c348a3 100644
--- a/trail/trail.go
+++ b/trail/trail.go
@@ -86,6 +86,7 @@ type Option struct {
 	Regions       []string
 	AllAccounts   bool
 	AllRegions    bool
+	LogFilePrefix string
 }
 
 type WalkEventsFunc func(r *Record) error
@@ -231,6 +232,9 @@ func generatePrefixes(sess *session.Session, dsn string, opt Option, after1Day b
 	}
 	bucket := splitted[0]
 	prefix := "AWSLogs"
+	if opt.LogFilePrefix != "" {
+		prefix = fmt.Sprintf("%s/%s", opt.LogFilePrefix, prefix)
+	}
 	if len(splitted) > 1 && splitted[1] != "" {
 		prefix = splitted[1]
 	}