Would it be faster if you do reading and moving using a shell script?

Something like:

for afile in $dir/*; do
  achannel=$(awk -F'|' '{print $20}' "${afile}")
  mv "${afile}" "${outdir}/${achannel}"
done
[download]

Unlikely. Creating an awk and a mv process for each of half a million files sums up to spawning a million processes. I doubt that this idea will be faster than running a single process (perl script), even on an insanely fast machine.

Alexander