cat postgresql.conf | grep -v "^$" | grep -v "^#"

SLEEP=$1
/bin/bash -c "while true ; do continue ; done" & pid=$!
sleep $SLEEP
kill -9 $pid

grep “hhb” -A/B 1

echo "12:90,45:90" | tr , '.'
用点替代其中的逗号

 72 # run program and do not display the output
 73 function run_quiet()
 74 {
 75 	local cmd=$*
 76 	$cmd >/dev/null 2>&1
 77 	return $?
 78 }
 79
 80 # run program in background and echo the reture value to a temp file if finished
 81 function run_bg()
 82 {
 83 	local flag_file=$1
 84 	shift
 85 	local cmd=$*
 86 	run_quiet $cmd
 87 	echo $? > $flag_file
 88 }

VMM_SSH_Time_Out() {
	echo '' > /root/.ssh/known_hosts
	local host=$1
	local time_out=$2
	shift;shift
	local command=$@
	echo $command
	local exp_cmd=`cat << EOF
	eval spawn ssh $host "$command"
	set timeout $time_out
	expect {
		"*assword:" { send "123456\r"; exp_continue}
		"*(yes/no)?" { send "yes\r"; exp_continue }
		eof  { exit [ lindex [wait] 3 ] }
	}
   		EOF`
	expect -c "$exp_cmd"
	# if ssh failed because of time out, it will return 255
	return $?
}

 #!/usr/bin/expect
 # 设置超时时间为 60 秒
 set timeout  60
 # 设置要登录的主机 IP 地址
 set host hsw-ep1
 # 设置以什么名字的用户登录
 set name root
 # 设置用户名的登录密码
 set password 123456

 #spawn 一个 ssh 登录进程
 spawn  ssh $host -l $name
 # 等待响应，第一次登录往往会提示是否永久保存 RSA 到本机的 know hosts 列表中；等到回答后，在提示输出密码；之后
就直接提示输入密码
 expect {
"(yes/no)?" {
send "yes\n"
expect "assword:"
send "$pasword\n"
}
"assword:" {
send "$password\n"
}
 }
 expect "#"
 # 下面测试是否登录到 $host
 send "uname\n"
 expect "Linux"
 send_user  "Now you can do some operation on this terminal\n"
 # 这里使用了 interact 命令，使执行完程序后，用户可以在 $host 终端进行交互操作。
 interact