Projects and resources (En) > Tips and tricks

Batch converting PNG to JPG with convert from the ImageMagick suite



All is here:

--- Citer --- 10 down vote

The convert command found on many Linux distributions is installed as part of the ImageMagick suite. Here's the bash code to run convert on all PNG files in a directory and avoid that double extension problem:

--- Code: ---for img in *.png; do
    convert "$filename.png" "$filename.jpg"
--- Fin du code ---

--- Fin de citation ---

This is the one I just used, I ended with both png and jpg files in the same directory, which was the perfect result.

--- Citer ---I have a couple more solutions.

The simplest solution is like most already posted. A simple bash for loop.

--- Code: ---for i in *.png ; do convert "$i" "${i%.*}.jpg" ; done
--- Fin du code ---

For some reason I tend to avoid loops in bash so here is a more unixy xargs approach, using bash for the name-mangling.

--- Code: ---ls -1 *.png | xargs -n 1 bash -c 'convert "$0" "${0%.*}.jpg"'
--- Fin du code ---

The one I use. It uses GNU Parallel to run multiple jobs at once, giving you a performance boost. It is installed by default on many systems and is almost definitely in your repo (it is a good program to have around).

--- Code: ---ls -1 *.png | parallel convert '{}' '{.}.jpg'
--- Fin du code ---

The number of jobs defaults to the number of processes you have. I found better CPU usage using 3 jobs on my dual-core system.

--- Code: ---ls -1 *.png | parallel -j 3 convert '{}' '{.}.jpg'
--- Fin du code ---

And if you want some stats (an ETA, jobs completed, average time per job...)

--- Code: ---ls -1 *.png | parallel --eta convert '{}' '{.}.jpg'
--- Fin du code ---

There is also an alternative syntax if you are using GNU Parallel.

--- Code: ---parallel convert '{}' '{.}.jpg' ::: *.png
--- Fin du code ---

And a similar syntax for some other versions (including debian).

--- Code: ---parallel convert '{}' '{.}.jpg' -- *.png
--- Fin du code ---

--- Fin de citation ---

More on the above linked page.


[0] Index des messages

Utiliser la version classique