How can I batch with ImageMagick command?

Question

I'm doing

convert dead0000.bmp -alpha on -fill none -draw 'color 0,0 replace' dead0000.png

but I have a few thousand files. Is there any way to just do the whole directory at once?

Answer 1

A simple for loop in Bash, macOS' default shell, would suffice:

for f in *.bmp; do convert "$f" -alpha on -fill none -draw 'color 0,0 replace' "${f%%.bmp}.png"; done

It uses string manipulation to replace the file extension for the output file. Here:

• "$f" is the original input filename
• "${f}" is the same, just a different way of accessing the variable
• "${f%%.bmp}.png" uses string replacement – f%%.bmp means, delete the longest match of .bmp from the back of $f.

Answer 2

have a look at this. mogrify is a powerful scripting tool for imagemagick http://www.imagemagick.org/script/mogrify.php (and *.bmp)