shell读取某个文件最后一行,读到关键字后继续执行

#!bin/bash

c=`tail -1 server.log |grep -i 'Admin server listen on \[0.0.0.0:19200\]' |wc -l`
until [ $c -eq 1]
do
 sleep 5
 c=`tail -1 server.log |grep -i 'Admin server listen on \[0.0.0.0:19200\]' |wc -l`
done

echo ok