[ Linux ] : Bash script

# Create folder named with month : 

printf '%s\n' {1..12}/01 | xargs -I {} date -d {} +%b | xargs mkdir --

# Create folder named with day:

cd Jan && for i in {1..31} ; do mkdir -p $i; done && cd .. && cd Feb && for i in {1..28} ; do mkdir -p $i; done && cd .. && cd Mar && for i in {1..31} ; do mkdir -p $i; done && cd .. && cd Apr && for i in {1..31} ; do mkdir -p $i; done && cd .. && cd May && for i in {1..31} ; do mkdir -p $i; done && cd .. && cd Jun && for i in {1..30} ; do mkdir -p $i; done && cd .. && cd Jul && for i in {1..31} ; do mkdir -p $i; done && cd .. && cd Aug && for i in {1..31} ; do mkdir -p $i; done && cd .. && cd Sep && for i in {1..30} ; do mkdir -p $i; done && cd .. && cd Oct && for i in {1..31} ; do mkdir -p $i; done && cd .. && cd Nov && for i in {1..30} ; do mkdir -p $i; done && cd .. && cd Dec && for i in {1..31} ; do mkdir -p $i; done && cd ..