shell script objeto más antiguo de un directorio

http://www.daniweb.com/software-development/shell-scripting/threads/288013/sort-oldest-5-files-in-a-directory-tree-recursively-based-on-timestamp-linux

lsof shell script: un comando muy útil e interesante

http://www.akadia.com/services/lsof_quickstart.txt

if en shell script

http://tldp.org/LDP/Bash-Beginners-Guide/html/sect_07_01.html