Files found
Make sure you are using exiftool to look for usersnames in files exiftool finds/*.pdf|grep -i creator|cut -d ':' -f 2| sort -u|sed 's/ //g'
exiftool finds/* -r| sort -u
exiftool finds/* -r|cut -d ':' -f 2| sort -u
exiftool finds/* -r|egrep -i (creator|description|modified|author|info|user)|cut -d ':' -f 2| sort -u