求批量把255.255.255.0,255.255.255.254,255.255.255.252,以此类推，转换成/多少格式

zhuxw112233

求批量把255.255.255.0,255.255.255.254,255.255.255.252,以此类推，转换成/多少格式的脚本

如：

255.255.255.0       /24
255.255.255.254   /31
255.255.255.252   /30

wh7211

回复 1# zhuxw112233

1. cat 1
   
2. 255.255.255.0
   
3. 255.255.255.254
   
4. 255.255.255.252
   
5. 
   
6. awk -F"." '{for(i=1;i<=NF;i++){if($i==255){a+=8}else if($i==0){printf("%-18s/%s\n",$0,a)}else{for(j=1;j<=7;j++){b=b?b+2**(8-j):2**(8-j);if($i==b){printf("%-18s/%s\n",$0,a+j);break}}}};a=b=0}' 1
   
7. 255.255.255.0     /24
   
8. 255.255.255.254   /31
   
9. 255.255.255.252   /30

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