shell数组

1. seq [FIRST [INCREMENT]] LAST
-s: –separator=STRING
-w: –equal-width

seq -s'#' 1 20 | sed 's/[0-9]*//g'
seq -w 1 10 100

2. list & array

list=$(seq 100)
list=$(echo {1..100}) # more efficient

array=($(seq 100))
array=($(echo {1..100})