percentile.sh

#!/bin/bash

# stdin should be integers, one per line.
# command line perncentiles e.g. 75 90 95

percentiles=$*
tmp="$(mktemp -t percentileXXXX)"
total=$(sort -n | tee "$tmp" | wc -l)

for percentile in $percentiles
do
  count=$(((total * percentile + 99) / 100))
  echo "$percentile: $(head -n $count "$tmp" | tail -n 1)"
done
rm "$tmp"