/prefix_to_mask.sh
Last active Mar 3, 2018
| #!/bin/bash | |
| # date: 2018-03-03 | |
| # license: GPLv3 https://www.gnu.org/licenses/gpl-3.0.txt | |
| # author: nanpuyue <nanpuyue@gmail.com> https://blog.nanpuyue.com | |
| num=$(( 4294967296 - 2**(32-$1) )) | |
| for i in {3..0};do | |
| echo -n $(( $num / 256**$i )) | |
| num=$(( $num % 256**$i )) | |
| [[ $i = 0 ]] && echo || echo -n . | |
| done |
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