diff --git a/shell/bashrc b/shell/bashrc
index 46a02d8..e2e0b0b 100644
--- a/shell/bashrc
+++ b/shell/bashrc
@@ -204,6 +204,12 @@ DATE=$(/bin/date +%Y-%m-%d_%H:%M:%S.%N)
 local TMPFILE=tmp.${DATE}.sw
 mv "$1" $TMPFILE && mv "$2" "$1" && mv $TMPFILE $2
 }
+bf()
+{
+DATE=$(/bin/date +%Y-%m-%d_%H:%M:%S.%N)
+local TMPFILE=tmp.${DATE}.bak
+/bin/cp "$1" $TMPFILE
+}
 fi
 
 #date() {