#!/bin/bash
# take a screenshot.  output is png.  If no output file is specified
# on the command line, uses yyyy-mm-ddThh-mm-ss.png

outfile=$(date +%FT%H:%M:%S.png)
if [ ! -z $1 ]; then outfile=$1; fi

xwd | xwdtopnm | pnmtopng > $outfile