Links pictures over a certain width (and ratio) to a new directory

wider-than.sh

#!/bin/sh
[ $1 != '' ] || exit 1
source=$1
width=$2
IFS='
'
debug=1
mkdir -p $width 
for n in $(find $source -type f -regextype posix-egrep \
    -regex '.*.(png|jpg|jpeg|gif)') ; do 
    filename=$(echo $n | cut -d/ -f2)
    if [ -f $width/"$filename" ] ; then
        if [ $debug ] ; then
            echo "$filename: Already linked."
        fi
        continue
    fi
    result=$(gm identify -format %f:%w:%h "$n" 2> /dev/null)
    w=$(echo $result | cut -d: -f2)
    h=$(echo $result | cut -d: -f3)
    # Has a width? wider than our minimum? ratio between 1:1 and 2:1?
    if ! [ -z "$w" ] && [ $w -ge $width ] && [ $(echo $w/$h | bc) -eq 1 ]; then 
        if [ $debug ] ; then
            echo "$filename ($w x $h): Linking"
        fi
        ln -sf ../"$n" $width  
    fi  
done