I often come across files than are named 1..9 and then go to 10…99. The problem is many Linux programs begin with 1, then go to 10, etc. The sorting is wrong. Fortunately the rename command comes to our rescue:

rename 's/\d+/sprintf("%05d", $&)/e' *.jpg

Running the above command looks for numbers in the name of JPG files (in the current directory) and renames the file to ensure there are 5 digits in the filename. Now, instead of 1.jpg, your file will be named 00001.jpg. Handy.

Thanks to this forum for the information.