#! /usr/bin/gawk -f
# Last edited on 2003-10-12 12:30:27 by stolfi

# Reads the output of `ls -Abs1 --block-size=1 /var/spool/mail' 
# executed twice 1000 seconds apart, and prints a list showing 
# the (estimated) total mail received by each user in that interval.

BEGIN {
  split("", msize);
  split("", mrecv);
}

(NF != 2){ printf "NF = %d: \"%s\"\n", NF, $0 > "/dev/stderr"; next; }

/^total/{ next; }

($2 ~ /[^a-z0-9]/) { next; }

/./ { 
  sz = $1; uid = $2;
  if ((uid in msize) && (sz > msize[uid])) { mrecv[uid] += (sz - msize[uid]); }
  msize[uid] = sz;
}

END {
  tot = 0;
  for (uid in mrecv)
    { printf "%9d %s\n", mrecv[uid], uid; tot += mrecv[uid] }
  printf "\n%9d TOTAL\n", tot;
}