Code to generate graphic of Mefi favoriting data

#!/bin/sh
# extract postid and datestamp (in secs since epoch)
sed 1,2d postdata_mefi.txt \
    |awk -F '\t' '$1 ~ /^980..$/ {print $1,$3}' \
    |while read postid datestamp; do
        echo $postid $(date -d "$datestamp" +%s);
    done \
    |sort -k1b,1 \
    >posts
sed 1,2d favoritesdata.txt \
    |awk -F '\t' '$4 == 2 && $6 ~ /^980..$/ {print $6,$7}' \
    |while read postid datestamp; do
        echo $postid $(date -d "$datestamp" +%s);
    done \
    |sort -k1b,1 \
    >favs

# convert fav timestamps to time-since-post, first 24 hours only,
# bin into 30-minute bins
join -j1 posts favs \
    |awk '{print $1, int(($3-$2)/(30*60))}' \
    |sort -k1b,1 -k2 -n \
    |uniq -c \
    |awk '$3 < 48 {printf "%d:%02d %d\n",$2,$3,$1}' \
    |sort -k1b,1 \
    >x
# add zero lines
seq 98000 98099 \
    |while read n; do seq -f "$n:%02.0f" 0 47; done \
    |join -j1 -a1 - x \
    |awk '$2 == "" {$2=0} {print}' \
    >data

# make graphs
seq 98000 98099 |while read n; do
echo $n >&2
(cat <<EOF
%!PS-Adobe-3.0 EPSF-3.0
%%BoundingBox: 0 0 49 49
1 setlinewidth
0.5 0.5 translate
gsave
0 0 0 setrgbcolor
1 1 translate
/bar { exch 0 moveto 0 exch rlineto stroke } def
EOF
grep "^$n:" data |sed -e 's,^.*:,,' -e 's,$, bar,'
cat <<EOF
grestore
0.5 0.5 0.5 setrgbcolor
0 0 moveto 0 48 lineto 48 48 lineto 48 0 lineto closepath stroke
%%EOF
EOF
) |convert eps:- $n.png
done
montage -geometry +1+1 980*.png montage.png