Shell Programming and Scripting

There is if you care about handling filenames that have any IFS characters. Assuming that IFS has its default value, your code will choke on any filename that contains a space, tab, or newline.

Also, there is no way to fix that shortcoming. If you double-quote the command substitution in the for loop's list, it will always result in a list with a single item.

The shell substitution that the original poster's code uses works correctly and is part of the posix standard. Your subsitution is an extension and will mishandle filenames with an embedded ".JPG" sequence (though such a filename may be unlikely, the limitation should be mentioned).

Code:

$ f=image.JPG.JPG
$ echo ${f/JPG/jpg}
image.jpg.JPG

Regards,
Alister

---------- Post updated at 02:38 AM ---------- Previous update was at 02:34 AM ----------

That's a very nice approach, but alas rename is not a standardized utility and may not be present. If it is, your approach is most convenient.

By the way, you could speed it up by not having to invoke rename once per filename, using:

Code:

find -name '*.JPG' -exec rename .JPG .jpg {} +

Also, I get the impression, from reading the man page, that your solution may incorrectly rename files that contain an embedded .JPG before the end of the filename. It may be an uncommon scenario, but still, for completeness' sake, I mention it.

Regards,
Alister