Time to first stable linux release

output.txt

3.00: 2011-07-22 -> 2011-08-05 = 14 days
3.01: 2011-10-24 -> 2011-11-11 = 18 days
3.02: 2012-01-04 -> 2012-01-12 = 8 days
3.03: 2012-03-18 -> 2012-04-02 = 14 days
3.04: 2012-05-20 -> 2012-06-01 = 12 days
3.05: 2012-07-21 -> 2012-08-09 = 19 days
3.06: 2012-09-30 -> 2012-10-07 = 7 days
3.07: 2012-12-11 -> 2012-12-17 = 6 days
3.08: 2013-02-18 -> 2013-02-28 = 10 days
3.09: 2013-04-29 -> 2013-05-08 = 9 days
3.10: 2013-06-30 -> 2013-07-13 = 13 days
3.11: 2013-09-02 -> 2013-09-14 = 12 days
3.12: 2013-11-03 -> 2013-11-20 = 17 days
3.13: 2014-01-20 -> 2014-01-29 = 9 days
3.14: 2014-03-31 -> 2014-04-14 = 14 days
3.15: 2014-06-08 -> 2014-06-16 = 8 days
3.16: 2014-08-03 -> 2014-08-14 = 11 days
3.17: 2014-10-05 -> 2014-10-15 = 10 days
3.18: 2014-12-07 -> 2014-12-16 = 9 days

time-to-first-stable.sh

#!/bin/sh

uri=http://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/tag/?id=v3

datediff() {
  printf -- '%d' $(( ( $(date -d $1 +%s) - $(date -d $2 +%s) ) / 86400))
}

reldate() {
  curl -s ${uri}.${1} |
    awk 'BEGIN { FS=">" }; />tag date</ { print $5 }' |
    cut -d' ' -f1
}

for i in $(seq 0 18); do
  a=$(reldate $i)
  b=$(reldate ${i}.1)
  printf '3.%02d: %s -> %s = %d days\n' $i $a $b $(datediff $b $a)
done