juretta.com

Let's assume that you have a bunch of images for which you want to create thumbnails. The thumbnails should be rotated 90 degrees counter clockwise (that is 270 degrees clockwise), scaled to a specific size and renamed from abc_large.png to abc_thumb.png.

powerbook:~ sts$ cat convert.sh
#!/bin/bash

# create directory for thumbnails
mkdir thumbs

# the large images are in ./images

for i in $(ls images/*.png)
do

# Rotate all images
img=`basename $i`
`convert -rotate 270 $i thumbs/$img`
echo "rotate $img"


# scale all images. replace suffix
new_name=`echo $img | sed s/_large/_thumb/`
`convert -scale 40x120 thumbs/$img thumbs/$new_name`
echo "scale thumbs/$new_name"


done

The following snippet crops all images in the current working directory to 222px x 185px. Furthermore the image type will be changed from gif to jpeg using the original image name. And all in one line of shell script.

Welcome to Darwin!
macbook-sts:~ stefan$ cd ~/images/
macbook-sts:~ stefan$ for i in $(ls); do name=`echo $i | sed s/\.gif/\.jpg/g`;\
convert -crop 222x185+0x0 $i $name; done