The oneliner is written for the Bourne shell (bash), and uses cksum in combination with ruby. This should be one long line; replace the line break with a single space when you enter the function:
function crc32 { cksum -o3 "$@"|ruby -e 'STDIN.each{|a|a=a.split;printf
"%08X\t%s\n",a[0],a[2..-1].join(" ")}'; }
Here's an example of the new function in use:
$ cd "/Library/Desktop Pictures/"
$ crc32 Aqua\ Blue.jpg
FEDCA2D9 Aqua Blue.jpg
$ crc32 *.png
59B02128 Small Ripples graphite.png
FA28E0A8 Small Ripples.png
You can also put the function in your .bash_profile so you can use the crc32 command in all your Terminals. Of course there are existing CRC32/SFV tools and this is not to replace them, but this is a nice alternative making use of the standard tools that come with the OS.

