Crop square image to circle.

to-circle.sh

#!/bin/bash
#
# usage: to-path.sh files(to crop circle)
#

for path in "$@"
do
  convert $path \( +clone -threshold -1 -negate -fill white -draw "circle `identify -format %w $path | awk '{print $1/2}'`, `identify -format %h $path | awk '{print $1/2}'` `identify -format %w $path | awk '{print $1/2}'`, 0" \) -alpha Off -compose copy_opacity -composite circle-`basename $path`
done