经典shell面试题整理
经典shell面试题整理
一、取出/etc/passwd文件中shell出现的次数
问题:下面是一个/etc/passwd文件的部分内容。题目要求取出shell并统计次数,shell是指后面的/bin/bash,/sbin/nologin等,如下面/bin/bash出现12次,/sbin/nologin出现3次。
- 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
二、文件整理
问题: employee文件中记录了工号和姓名- employee.txt:
- 100 Jason Smith
- 200 John Doe
- 300 Sanjay Gupta
- 400 Ashok Sharma
- bonus.txt:
- 100 $5,000
- 200 $500
- 300 $3,000
- 400 $1,250
处理结果:
- 400 ashok sharma $1,250
- 100 jason smith $5,000
- 200 john doe $500
- 300 sanjay gupta $3,000
- paste employee.txt bonus.txt | awk '{print $1,$2,$3,$5}'|tr '[:upper:]' '[:lower:]'|sort -k 2
- 100 Jason Smith 100 $5,000
- 200 John Doe 200 $500
- 300 Sanjay Gupta 300 $3,000
- 400 Ashok Sharma 400 $1,250
sort命令对字符排序。sort -k 2表示按文件第2个域排序,这里第二个域为姓名,所以是按姓名升序排序。如果要降序排列,则要用sort -k 2r。
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