简介

在bash里冒号和躺着的冒号的用法不一样一定要注意别用错。

躺着的冒号是两个点

难道正常的不是两个点）的作用：
A sequence expression takes the form {x…y[…incr]}, where x and y are either integers or single characters, and incr, an optional increment, is an integer. When integers are supplied, the expression expands to each number between x and y, inclusive. Supplied integers may be prefixed with 0 to force each term to have the same width. When either x or y begins with a zero, the shell attempts to force all generated terms to contain the same number of digits, zero-padding where necessary. When characters are supplied, the expression expands to each character lexicographically between x and y, inclusive, using the default C locale. Note that both x and y must