greymd/gist:c586bbbcfd4904178257

## gistfile1.sh
# GNU版grepを利用
 echo 2" "{1..2015}$'\n' | awk NF | while read m y; do echo -n "$y年"; cal $m $y | awk NF | sed -n -e '3,3p' -e '$,$p' | tr -d '\n' | awk '$0=":"NF' ;done | grep -oP ".+(?=:13)"

#ピッタリと収まる例
#    $ cal 2 2015
#       February 2015
#    Su Mo Tu We Th Fr Sa
#     1  2  3  4  5  6  7
#     8  9 10 11 12 13 14
#    15 16 17 18 19 20 21
#    22 23 24 25 26 27 28

# 収まらない例
#    $ cal 2 2014
#       February 2014
#    Su Mo Tu We Th Fr Sa
#                       1
#     2  3  4  5  6  7  8
#     9 10 11 12 13 14 15
#    16 17 18 19 20 21 22
#    23 24 25 26 27 28
	# GNU版grepを利用
	echo 2" "{1..2015}$'\n' \| awk NF \| while read m y; do echo -n "$y年"; cal $m $y \| awk NF \| sed -n -e '3,3p' -e '$,$p' \| tr -d '\n' \| awk '$0=":"NF' ;done \| grep -oP ".+(?=:13)"

	#ピッタリと収まる例
	# $ cal 2 2015
	# February 2015
	# Su Mo Tu We Th Fr Sa
	# 1 2 3 4 5 6 7
	# 8 9 10 11 12 13 14
	# 15 16 17 18 19 20 21
	# 22 23 24 25 26 27 28

	# 収まらない例
	# $ cal 2 2014
	# February 2014
	# Su Mo Tu We Th Fr Sa
	# 1
	# 2 3 4 5 6 7 8
	# 9 10 11 12 13 14 15
	# 16 17 18 19 20 21 22
	# 23 24 25 26 27 28