Bash script check if image is animated png (apng)

Question

Trying to figure out a way in my bash script to check if a file is an animated PNG (apng) file. In my case I want to ignore it if it is . Any ideas ?

UPDATE: The answer

Answer 1

First extract the extension of your file using expr.

Check http://tldp.org/LDP/abs/html/string-manipulation.html:

expr match "$string" '.*\($substring\)'

Extracts $substring at end of $string, where $substring is a regular expression.

Then compare extracted extension with ".png"