Convert integers to Extended Value format (bourne shell):
ev_map="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-." int_to_ev() { int="${1}" if [ ! "${int}" ] then printf "__" return fi [ "${int}" -lt 0 ] && int=0 [ "${int}" -gt 4095 ] && int=4095 hob=$(( ( ${int} / 64 ) + 1 )) lob=$(( ( ${int} % 64 ) + 1 )) printf "%s%s" "$(echo "${ev_map}" | cut -c${hob})" "$(echo "${ev_map}" | cut -c${lob})" } src_data() { cat link-20100704.log | awk -F'\t' '{ print $2 "\t" $1 }' } printf "http://chart.apis.google.com/chart?cht=lc&chs=1000x256&chd=e:"; src_data | head -n 768 | while read time rtt do int_to_ev $(( ${rtt} / 10 )) done