ImageMagick on multiple files

Question

I have converted a single file from BMP to PNG with ImageMagick's convert using the command below

convert CD\ Front.bmp CD\ Front.png

I have many such files, thus I tried:

for f in */*.bmp ; do convert $f ${f%bmp}png; done

but this command hangs forever.

What am I doing wrong?

Solution 1

You most likely have a problem because you don't quote the file names:

for f in */*.bmp ; do convert "$f" "${f%bmp}png" ; done
#                             ^  ^ ^           ^

do this so the space in the file names do not cause problems.

Solution 2

You can use mogrify:

mogrify -format png *.bmp

Source: Imagemagick website

Solution 3

I would refactor the code like this. I find this method to be clearer & easier to debug:

find . -type f -name '*.bmp' |\
  while read BMP
  do
    DIR=$(dirname "$BMP")
    PNG="$(echo $BMP | sed 's/.bmp//g')"
    convert "${BMP}" "${PNG}".png
  done

Comments

[Mat]

$f should be quoted too

[Zelda]

You are right, thank you for pointing out

[evilsoup]

Quoting the variables is correct, but if you quote the glob then the shell will look for a literal */*.bmp.

[Zelda]

Thanks to you as well. I should try out my solutions before posting...

[Anthon]

I took the liberty to change JPEG into PNG while reviewing

[Giacomo1968]

Ahh, thanks. But it did work for JPEG’s as well!

[Anthon]

Yes, guess it does, but it was not what the OP asked for ;-)

[Kevin]

Don't use find | while read, especially when a glob will suffice.

[Kevin]

And the sed would be better as 's/\.bmp$/.png/', then obviously remove the .png from the actual command