plot memory by search literal

plot(){
 TMP=/tmp;
 if [ -z "$1" ]
 then
  if [ "$TERM" == "xterm" ];
  then
   PROGNAME="$(dialog 'Enter the search literal:' 7 $COLUMNS)"
   [ -z "$PROGNAME" ] && PROGNAME=$(zenity --entry --text 'Enter the search literal');
   [ -z "$PROGNAME" ] && exit 2
  else
   if [ "$TERM" == "dumb" ];
   then
    PROGNAME=$(zenity --entry --text 'Enter the search literal');
   else
    exit 6;
   fi
  fi
 else
  PROGNAME="$1";
 fi
 [ -e "$TMP/memory_usage_$PROGNAME_$$.dat" ] && exit 1;
 COUNT=100;
 [ -n "$2" ] && COUNT="$2";
 printf "Gathering data:";
 unset GNUPLOT_CMD;
 GNUPLOT_CMD=(plot);
 while [ ${#GNUPLOT_CMD[*]} -le $[$(ps avx | grep -F $PROGNAME | wc -l)-1] ];
 do
  if [ ${#GNUPLOT_CMD[*]} -lt $[$(ps avx | grep -F $PROGNAME | wc -l)-1] ];
  then
   GNUPLOT_CMD[${#GNUPLOT_CMD[*]}]="'$TMP/memory_usage_$PROGNAME_$$.dat' using 1:$[${#GNUPLOT_CMD[*]}+1] with lines ti '$(ps avx | grep -F $PROGNAME | sed -r s/'^( *[^ ]*){9} '//g | tail -n+${#GNUPLOT_CMD[*]} | head -1)',";
  else
   GNUPLOT_CMD[${#GNUPLOT_CMD[*]}]="'-' using 1:$[${#GNUPLOT_CMD[*]}+1] with lines ti '$(ps avx | grep -F $PROGNAME | sed -r s/'^( *[^ ]*){9} '//g | tail -n+${#GNUPLOT_CMD[*]} | head -1)';";
  fi
 done
 (echo "set ylabel 'Memory Usage' textcolor lt 1;${GNUPLOT_CMD[*]}";
 INDEX=0;
 while [ $INDEX -lt $COUNT ];
 do
  printf "$INDEX ";
  ps avx | grep -F $PROGNAME | sed s/"^.*S+.*0:00      .............   ...  0.0 grep -F [${PROGNAME:0:1}]${PROGNAME:1}$"// | awk '{print $8}' | tr "n" " ";
  INDEX=$[$INDEX+1];
  printf . 1>&2;
 done; ) | sed s/'^ '// | sed s/'  '/\n/g | tee "$TMP/memory_usage_$PROGNAME_$$.dat" | gnuplot -persist;
 rm -f $TMP/memory_usage_$PROGNAME_$$.dat;
 echo;
}