如何在自动bash脚本中发送存储值而不是别名进行交互式输入

Question

I'm trying to automate the installation of mysql on a remote sever. I'm using golang to do various things, one of which is executing an expect script in bash that has several steps. One of the steps is installing mysql and then running mysql_secure_installation . The first prompt it asks the user for is a password. This password is created at runtime so I don't know it ahead of time to include it as a literal value that I can send . I get the password from the log and store that in a variable, but how do I take that value and send it to be used within a prompt. I know I want to send it but I think I keep sending the alias and not the value as I am getting an access error. How do I send the value and not the alias? I'm kind of new to expect scripting so any insight is appreciated.

expect script as produced with golang:

/usr/bin/expect -c:
spawn ssh root@a.b.c.d
sleep 3
expect "# "
send "yum -y update\r"
sleep 10
expect "# "
send "yum -y upgrade\r"
sleep 10
expect "# "
send "yum -y localinstall https://dev.mysql.com/get/mysql80-community-release-el7-1.noarch.rpm\r"
sleep 8
expect "# "
send "yum -y --disablerepo=mysql80-community --enablerepo=mysql57-community install mysql-community-server\r"
sleep 5
expect "# "
send "service mysqld start\r"
sleep 3
expect "# "
send "temppass=\$\(grep 'A temporary password is generated for root@localhost' /var/log/mysqld.log | tail -l\)\r"
sleep 1
expect "# "
send "shortpass=\${temppass:\(-12\)}\r"
sleep 1
expect "# "
send "echo \$shortpass\r"
sleep 1
expect "# "
send "mysql_secure_installation\r"
sleep 10
expect "Enter password for user root: "
send "\$shortpass\r"
sleep 10
expect "New password: "
send "<pass>\r"
sleep 10
expect "Re-enter new password: "
send "<pass>\r"
sleep 10
expect "Change the password for root ? \(\(Press y|Y for Yes, any other key for No\) : "
send "y\r"
sleep 10
expect "New password: "
send "<pass>\r"
sleep 10
expect "Re-enter new password: "
send "<pass>\r"
sleep 10
expect "Remove anonymous users? \(Press y|Y for Yes, any other key for No\) : "
send "y\r"
sleep 10
expect "Disallow root login remotely? \(Press y|Y for Yes, any other key for No\) : "
send "n\r"
sleep 10
expect "Remove test database and access to it? \(Press y|Y for Yes, any other key for No\) : "
send "y\r"
sleep 10
expect "Reload privilege tables now? \(Press y|Y for Yes, any other key for No\) : "
send "y\r"
sleep 10

Actual output:

spawn ssh root@a.b.c.d
Last login: Mon Apr 29 13:25:07 2019 from t.x.y.z
[root@rias-e2e-server-a-segment-purv ~]# yum -y update
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
No packages marked for update
[root@rias-e2e-server-a-segment-purv ~]# yum -y upgrade
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
No packages marked for update
[root@rias-e2e-server-a-segment-purv ~]# yum -y localinstall https://dev.mysql.com/get/mysql80-community-release-el7-1.noarch.rpm
Loaded plugins: fastestmirror
mysql80-community-release-el7-1.noarch.rpm                                                                                                                                              |  25 kB  00:00:00     
Examining /var/tmp/yum-root-S1evUc/mysql80-community-release-el7-1.noarch.rpm: mysql80-community-release-el7-1.noarch
/var/tmp/yum-root-S1evUc/mysql80-community-release-el7-1.noarch.rpm: does not update installed package.
Nothing to do
[root@rias-e2e-server-a-segment-purv ~]# yum -y --disablerepo=mysql80-community --enablerepo=mysql57-community install mysql-community-server
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
Package matching mysql-community-server-5.7.26-1.el7.x86_64 already installed. Checking for update.
Nothing to do
[root@rias-e2e-server-a-segment-purv ~]# service mysqld start
Redirecting to /bin/systemctl start mysqld.service
[root@rias-e2e-server-a-segment-purv ~]# temppass=$(grep 'A temporary password is generated for root@localhost' /var/log/mysqld.log | tail -l)
[root@rias-e2e-server-a-segment-purv ~]# shortpass=${temppass:(-12)}
[root@rias-e2e-server-a-segment-purv ~]# echo $shortpass
e3H-*HGHu__7
[root@rias-e2e-server-a-segment-purv ~]# mysql_secure_installation

Securing the MySQL server deployment.

Enter password for user root: 
Error: Access denied for user 'root'@'localhost' (using password: YES)
[root@rias-e2e-server-a-segment-purv ~]# <pass>
-bash: Mysqlpass1!: command not found
[root@rias-e2e-server-a-segment-purv ~]# <pass>
-bash: Mysqlpass1!: command not found
[root@rias-e2e-server-a-segment-purv ~]# y
-bash: y: command not found
[root@rias-e2e-server-a-segment-purv ~]# <pass>
-bash: Mysqlpass1!: command not found
[root@rias-e2e-server-a-segment-purv ~]# <pass>
-bash: Mysqlpass1!: command not found
[root@rias-e2e-server-a-segment-purv ~]# y
-bash: y: command not found
[root@rias-e2e-server-a-segment-purv ~]# n
-bash: n: command not found
[root@rias-e2e-server-a-segment-purv ~]# y
-bash: y: command not found
[root@rias-e2e-server-a-segment-purv ~]#

Answer 1

Turns out the best thing to do is to use a programming language to inject whatever you want. I did this by exiting the sequence of commands that I wanted to run after the data I wanted was printed to the screen. At that point the buffer has the data I'm looking for, so I can get it from there and then continue with a new sequence that injects that value where I want.