Thanks to all. With interpret-trailers has been easy to make a simple script, also it checks if the Hash passed is a valid Object. I haven't found a simple way to mantain the blank line above the output of interpet-trailers (not even through cleanup). Follows the script, maybe could be usefull for somebody: #!/bin/sh for i in $* do git show $i &> /dev/null if [ $? = 0 ] then trailers+=" see-also=$i" fi done msg=$(cat /dev/null | ../git-interpret-trailers $trailers) git commit -m "$msg" -e -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html