CODEWITHSUNDEEP
bashimagemagick-convert
Niccolò
Niccolò

Reputation: 3092

How to automate conversion of images

I can convert an image like this:

convert -resize 50% foo.jpg foo_50.jpg

How can I automate such a command to convert all the images in a folder?

You can assume every image has .jpg extension.

A solution easily adaptable to automate the conversion of all the images inside the subdirectories of the working directory is preferable.

Upvotes: 0

Views: 89

Answers (3)

Benjamin W.
Benjamin W.

Reputation: 52132

You can use find -exec:

find -type f -name '*.jpg' -exec \
bash -c 'convert -resize 50% "$0" "${0%.jpg}"_50.jpg' {} \;

find -type f -name '*.jpg' finds all .jpg files (including those in subdirectories) and hands it to the command after -exec, where it can be referenced using {}.

Because we want to use parameter expansion, we can't use -exec convert -resize directly; we have to call bash -c and supply {} as a positional parameter to it ($0 inside the command). \; marks the end of the -exec command.

Upvotes: 1

Vinicius Placco
Vinicius Placco

Reputation: 1731

You can also try this (less elegant) one-liner using ls+awk:

ls *.jpg | awk -F '.' '{print "convert -resize 50% "$0" "$1"_50.jpg"}' | sh

this assumes that all the .jpg files are in the current directory. before running this, try to remove the | sh and see what is printed on the screen.

Upvotes: 0

choroba
choroba

Reputation: 241868

You can use a for loop with pattern expansion:

for img in */*.jpg ; do
    convert -resize 50% "$img" "${img%.jpg}"_50.jpg
done

${variable%pattern} removes the pattern from the right side of the $variable.

Upvotes: 3

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