remove double extensions in bash

Assuming:

• You only want to perform this in the current working directory (non-recursively)
• The double extensions have format precisely as .jpg.jpg:

Then the following script will work:

#!/bin/bashfor file in *.jpg.jpgdo    mv "${file}" "${file%.jpg}"done

Explanation:

• ${file%.jpg}: This part is called Parameter Subsitution.
• From the same source: "${var%Pattern} Remove from $var the shortest part of $Pattern that matches the back end of $var."
• Note that the "pattern" mentioned here is called globbing, which is different from regular expression in important ways.

To use this script:

• Create a new file called clean_de.sh in that directory
• Set it to executable by chmod +x clean_de.sh
• Then run it by ./clean_de.sh

A Note of Warning:

As @gniourf_gniourf have pointed out, use the -n option if your mv supports it.

Otherwise - if you have a.jpg and a.jpg.jpg in the same directory, it will rename a.jpg.jpg to a.jpg and in the process override the already existing a.jpg without warning.

One line rename command should also suffice (for your case at least):

rename 's/\.jpg\.jpg$/.jpg/' *.jpg.jpg

Here is a more general, but still easy solution for this problem:

for oldName in `find . -name "*.*.*"`; do newName=`echo $oldName | rev | cut -f2- -d'.' | rev`; mv $oldName $newName; done

Short explanation:
find . -name "*.*.* - this will find only the files with duplicate extensions recursively

echo $oldName | rev | cut -f2- -d'.' | rev - the trick happens here: the rev command do a reverse on the string, so you now you can see, that you want the whole filename from the first dot. (gpj.gpj.fdsa)

mv $oldName $newName - to actually rename the files

Release Notes: since it is a simple one-line script, you can find unhandled cases. Files with an extra dot in the filename, super-deep directory structures, etc.