This will rename all of your pictures in a given folder and prefix the date and time that the picture was taken in front of the file name.
Useful if your camera screws up your naming convention of your pictures, or if you want to simply organize all your pictures by date
yum install exiv2
cd to the folder with all your pictures that you want to rename
exiv2 -r'%Y%m%d-%H%M_:basename:' rename $(ls)
will rename to