1、統(tǒng)計出/etc/passwd文件中其默認(rèn)shell為非/sbin/nologin的用戶個數(shù)，并將用戶都顯示出來?
[root@centos7 ~]# grep -v "/sbin/nologin" /etc/passwd |wc -l && grep -v "/sbin/nologin" /etc/passwd |cut -d ":" -f1?
15?
root?
sync?
shutdown?
halt?
rick?
gentoo?
docker?
mongodb?
redis?
tomcat?
nginx?
ric?
mageia?
slackware?
test?
[root@centos7 ~]#?
2、查出用戶UID最大值的用戶名、UID及shell類型?
方法一：?
[root@centos7 ~]# cat /etc/passwd |sort -t: -k3 -nr |head -1 |cut -d: -f1,3,7?
方法二：?
[root@centos7 ~]# cat max_uid.sh?
#!/bin/bash?
uid=`cat /etc/passwd |cut -d ":" -f3`?
for i in $uid?
do?
?max=0?
?if [ $i -gt $max ]?
?then?
?max=$i?
?fi?
done?
grep $max /etc/passwd |cut -d ":" -f1,3,7?
[root@centos7 ~]# sh max_uid.sh?
test:2003:/bin/bash?
[root@centos7 ~]# tail -3 /etc/passwd?
mageia:x:1100:1100::/homenux:/bin/bash?
slackware:x:2002:2019::/home/slackware:/bin/tcsh?
test:x:2003:2003::/home/test:/bin/bash?
[root@centos7 ~]#?
3、統(tǒng)計當(dāng)前連接本機的每個遠(yuǎn)程主機IP的連接數(shù)，并按從大到小排序?
[root@centos7 ~]#ss -tnla |grep ESTAB |tr -s " " |cut -d " " -f5 |sort |uniq -c |sort -nr |head?
?119 127.0.0.1:3306?
?40 ::ffff:127.0.0.1:3306?
?21 ::ffff:59.39.91.244:3306?
?4 ::ffff:127.0.0.1:60009?
?2 127.0.0.1:55555?
?1 ::ffff:61.146.78.146:64634?
?1 ::ffff:61.143.130.174:30895?
?1 ::ffff:59.39.91.244:58830?
?1 ::ffff:59.39.91.244:58818?
?1 ::ffff:59.39.91.244:58263?
4、編寫腳本createuser.sh，實現(xiàn)如下功能:使用一個用戶名做為參數(shù)，如果指定參數(shù)的用戶存在，就顯示其存在，否則添加之;顯示添加的用戶的id號等信息?
[root@centos7 ~]# cat createuser.sh?
#!/bin/bash?
#********************************************************************?
#Author: rickzhu?
#QQ: 1779526363?
#Date: 2020-02-28?
#FileName：?createuser.sh?
#URL: http://www.magedu.com?
#Description：?The test script?
#Copyright (C): 2020 All rights reserved?
#********************************************************************?
if grep $1 /etc/passwd >/dev/null?
then?
?echo "$1 is exist."?
else?
?useradd $1?
?echo "`id $1`"?
fi?
[root@centos7 ~]# sh createuser.sh nginx?
nginx is exist.?
[root@centos7 ~]# sh createuser.sh test?
uid=2003(test) gid=2003(test) groups=2003(test)?
[root@centos7 ~]#?
5、編寫生成腳本基本格式的腳本，包括作者，聯(lián)系方式，版本，時間，描述等?
[root@centos7 ~]# cat createScript.sh?
#!/bin/bash?
#?
#判斷當(dāng)前目錄是否有同名的腳本?
if ls |grep $1 >>/dev/null?
then?
?echo "$1 is exist" && exit 10?
fi?

cat <<EOF > $1 && vim + $1?
#!/bin/bash?
#?
#********************************************************************?
#Author: rickzhu?
#QQ: 1779526363?
#Date: `date +%F`?
#FileName：?$1?
#Version 1?
#URL: http://www.magedu.com?
#Description：?The $1 script?
#Copyright (C): 2020 All rights reserved?
#********************************************************************?
EOF?
[root@centos7 ~]#?
[root@centos7 ~]# sh createScript.sh test.sh?
#!/bin/bash?
#?
#********************************************************************?
#Author: rickzhu?
#QQ: 1779526363?
#Date: 2020-02-28?
#FileName：?test.sh?
#Version 1?
#URL: http://www.magedu.com?
#Description：?The test.sh script?
#Copyright (C): 2020 All rights reserved?
#********************************************************************?
~? ?

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