Shell Programming and Scripting

find /directory/ -name "*.jpg" -exec mogrify -trim -fuzz 1% {} \;

$mogrify -verbose 1.jpg
1.jpg JPEG 100x171 100x171+0+0 8-bit DirectClass 8.99kb 
1.jpg JPEG 100x171 100x171+0+0 8-bit DirectClass 8.95kb

identify image.jpg | awk '{
   print gensub(/x/," ","",$3)}' |  #print space instead of 'x'
   while read w h ; do  #read in width and height 
       if [ $w = 0 ] || [ $h = 0 ] ; then 
          echo zero image 
       fi
   done

#!/bin/bash
# takes an image as argument and processes only if non-zero size

identify $1 | #get image info
  awk '{print gensub(/x/," ","",$3)}' |  #print size with space instead of 'x' 
    while read w h ; do  #read in width and height
         if [ $w = 0 ] || [ $h = 0 ] ; then            
            echo "$1 is zero image: width $w, height $h"
        else
            echo "processing image $1 ..."
            mogrify -trim -fuzz 1% $1        
        fi
    done

chmod u+x trimNonzero.sh

./trimNonzero.sh image.jpg

find $dir -name "*.jpg" -exec ./trimNonzero.sh {} \;