On Sunday 24 July 2011 10:13:30 R P Herrold wrote: > #!/bin/sh > # > CANDIDATES="pix00001.jpg pix00002.jpg pix00003.jpg" > for i in `echo "${CANDIDATES}"`; do > HASH=`echo "$i" | md5sum - | awk {'print $1'}` > echo "$i ${HASH}" > done I know it absolutelly has nothing to do with databases or files in folders but as we are talking about optimizing: #!/bin/bash CANDIDATES=(pix00001.jpg pix00002.jpg pix00003.jpg) for i in "${CANDIDATES[@]}"; do MD5SUM=$(md5sum <(echo $i)) echo "$i ${MD5SUM% *}"; done It's more than twice as fast than the previous sh script. [ willing to learn mode, feel free to ignore this] Anyway, about the the hashes and directories and so on... I assume we'd need a hash table in our application, right? Would we proceed as follows (correct me if I'm wrong please)? 1- m5sum the file we need 2- look for the first letter of the hash 3- get into the directory 4- now we look for our file Is this right? I understand this would improve the searching of files when there's a lot of them. Thanks to anyone that replies me and sorry for the offtopic Regards, Marc Deop