## 一、取出/etc/passwd文件中shell出現的次數 **問題**：下面是一個/etc/passwd文件的部分內容。題目要求取出shell并統計次數，shell是指后面的/bin/bash，/sbin/nologin等，如下面/bin/bash出現12次，/sbin/nologin出現3次。 ~~~ruby hyn:x:525:500::/home/hyn:/bin/bash ljlxx:x:526:500::/home/ljlxx:/bin/bash lzj:x:527:500::/home/lzj:/bin/bash wfly:x:528:500::/home/wfly:/bin/bash squid:x:23:23::/var/spool/squid:/sbin/nologin wyj:x:529:500::/home/wyj:/bin/bash qemu:x:107:107:qemu user:/:/sbin/nologin radvd:x:75:75:radvd user:/:/sbin/nologin dungbee:x:530:500::/home/dungbee:/bin/bash mysql:x:27:27:MySQL Server:/var/lib/mysql:/bin/bash scidb:x:531:531::/home/scidb:/bin/bash postgres:x:532:532::/home/postgres:/bin/bash crane:x:533:533::/home/crane:/bin/bash test:x:534:534::/home/test:/bin/bash hguser:x:535:535::/home/hguser:/bin/bash ~~~ cat /etc/passwd|awk -F: '{print $7}'|sort|uniq -c