user.txt and call_names.sh

[root@logstash ~]# cat user.txt 
zhangsan
lisi
wangwu
zhaoliu
liqi
zhangtao
lilei
hanmeimei
agou
amao
[root@logstash ~]# cat call_names.sh 
#!/bin/bash

while :
do
 line=$(cat /root/user.txt | wc -l)
 num=$[RANDOM%line+1]
 sed -n "${num}p" /root/user.txt
 sleep 5
 clear
done
[root@logstash ~]#

验证：

[root@logstash ~]# sh call_names.sh 
zhangtao
lisi
......
[root@logstash ~]#