Several shell interview questions and answers

Enterprise interview question 1:

It is known that the following strings are intercepted by the RANDOM random number variable md5sum | cut-c 1-8. Would you please crack the RANDOM corresponding numbers before the md5sum of these strings?

21029299

00205d1c

A3da1677

1f6d12dd

890684b

The idea of solving the problem: by passing one parameter at a time, it can be cracked in turn.

The range of $RANDOM is 0-32767

#! / bin/bash # Author: liuwei # Site: www.51liuzw.com for n in {0.32767} do MD5= `echo $n | md5sum | cut-c 1-8`if ["$MD5" = "$1"]; then echo "$n is." Exit else echo "$n no." Fi done

Note: you can also compare them all at once by defining an array.

#! / bin/bash # Author: liuwei # Site: www.51liuzw.com array= (00205d1c 21029299 a3da1677 1f6d12dd 890684b) for n in {0.32767} do MD5= `echo $n | md5sum | cut-c 1-8` For i in ${array [@]} Do if ["$MD5" = = "$I"]; then echo "$n and $I" > > c.log break else echo "$n no." Fi done done

# cat c.log

1346 and 00205d1c

7041 and 1f6d12dd

25345 and a3da1677

25667 and 21029299

Enterprise interview question 2: check whether multiple website addresses are normal in batch

Requirements: shell array method implementation, detection strategy as far as possible to simulate user access ideas

Http://www.baidu.com

Http://www.taobao.com

Http://www.51liuzw.com

Http://192.168.50.199

#! / bin/bash#Author: liuwei#Site: www.51liuzw.comarray= (http://www.baidu.comhttp://www.taobao.comhttp://www.51liuzw.comhttp://192.168.50.199)for n in ${array [*]}; do URL= `curl-I-m 2$ n 2 > / dev/null | egrep "200 | 302" | wc-l`if ["$URL"-eq 1] Then echo "$n is OK" else echo "$n is not OK" fidone

Results:

# sh test.sh

Http://www.baidu.com is OK

Http://www.taobao.com is OK

Http://www.51liuzw.com is not OK

Http://192.168.50.199 is not OK

Enterprise interview question 3: deal with the following with shell

1. Sort by the frequency of words in descending order!

2. Sort by alphabetical frequency in descending order!

The squid project provides a number of resources toassist users design,implement and support squid installations. Please browsethe documentation and support sections for more infomation

1. Sort by word frequency in descending order!

Solution: replace spaces with newline characters and sort statistics

# sed's # #\ nroomg' c.txt | sort | uniq-c

two。 Sort by alphabetical frequency in descending order!

Solution: use grep-o "\ w" to take the words apart and remove the symbols

# cat c.txt | grep-o "\ w" | sort | uniq-c