Rename images to exif time: Make unique filenames

You may want to try jhead instead which does that out-of-the-box (with a, b... z suffixes allowing up to 27 files with the same date) and doesn't have the stability issue mentioned by @meuh:

find . -iname '*jpg' -exec jhead -n%Y_%m_%d__%H_%M_%S {} +

Or using exiftool (example in man page):

exiftool -ext jpg '-FileName<CreateDate' -d %Y_%m_%d__%H_%M_%S%%-c.%%e .

(here with %-c being a numerical suffix starting with -)

My version of exiv2 (0.25 001900) will ask interactively what to do when the filename already exists.

exiv2: File `./2013_06_19__14_03_13.jpg' exists. [O]verwrite, [r]ename or [s]kip? 

By adding option -F it will instead automatically add an extra _1 (or _2 etc) to the name.

Renaming file to ./2013_06_19__14_01_53_1.jpg, updating timestamp

If the command is run a second time it says:

This file already has the correct name

and does nothing, but it gets confused if there is the _1 part, and will rename it _2. It will toggle like this in a non-destructive way on each run. You can ignore this if you like, or change your find pattern to ignore files matching the date pattern with an _ part.

For example, the regex pattern for the date format begins [0-9]{4}_[0-9]{2}_.... To simplify, I'll just look for a mix of 20 characters from the set 0..9 and _, which is regex [0-9_]{20}. To this the suffix of _ followed by at least 1 digit to look for is _[0-9]{1,}.jpg. Since the regex has to match the whole path, and not just the basename, the final regex including the directory is .*/[0-9_]{20}_[0-9]{1,}.jpg.

So you can use a find like:

find . -regextype posix-extended ! -iregex '.*/[0-9_]{20}_[0-9]{1,}.jpg' -iname '*.jpg' ...

Exiv2 can handle it on its own. I also spent a lot of time looking for help on this, until I went to see the exiv2 manual. The -F option solves this problem.

exiv2 -r'%Y_%m_%d__%H_%M_%S' -F *.jpg

It will append a _N at the end if the file already exist.

And for thoses who are looking for an option that allow create folder.

exiftool -r '-FileName<DateTimeOriginal' -d %Y/%m/%d/%%f%%-c.%%e *