如何使用正则表达式使用正则表达式匹配以“ $”结尾的内容？

我想使用来对远程服务器执行一些命令expect。但是，当我使用.*\$$它时，总是无法匹配远程提示来发送命令。

以下是我的脚本：

#!/bin/ksh
while read -r line; do
/usr/linux/bin/expect -c "
set timeout 20
spawn ssh padmin@$line
expect {
    -re \".*(P|p)assword:\" {send \"$2\r\"}
}
expect {
    -re \".*\$$\" {send \"ls -lt cfgbackups|grep gz|head -n 1|awk '{print \$9}'\r\"}
}
expect {
    -re \".*\$$\" {exit 0}
    eof {exit 0}
}
send_user \"$expect_out(1,string)\n\"
" 2>"$line".errlog &
done <"$1"

当我使用调试模式进行检查时，收到以下消息：

expect version 5.45.4
spawn ssh [email protected]
parent: waiting for sync byte
parent: telling child to go ahead
parent: now unsynchronized from child
spawn: returns {3474502}
Gate keeper glob pattern for '(P|p)assword:' is ''. Not usable, disabling the performance booster.

expect: does "" (spawn_id exp4) match regular expression "(P|p)assword:"? (No Gate, RE only) gate=yes re=no
[email protected]'s password: 
expect: does "[email protected]'s password: " (spawn_id exp4) match regular expression "(P|p)assword:"? (No Gate, RE only) gate=yes re=yes
expect: set expect_out(0,string) "password:"
expect: set expect_out(1,string) "p"
expect: set expect_out(spawn_id) "exp4"
expect: set expect_out(buffer) "[email protected]'s password:"
send: sending "padmin\r" to { exp4 }
Gate keeper glob pattern for '^:.*$' is ':*'. Activating booster.

expect: does " " (spawn_id exp4) match regular expression "^:.*$"? Gate ":*"? gate=no
"send_user"? no


expect: does " \r\n" (spawn_id exp4) match regular expression "^:.*$"? Gate ":*"? gate=no
"send_user"? no
Last unsuccessful login: Tue Jul  7 03:04:50 BEIST 2020 on ssh from 192.168.0.5
Last login: Tue Jul  7 15:18:11 BEIST 2020 on ssh from 192.168.0.4
Welcome!
/etc/profile[63]: hostname:  not found.

expect: does " \r\nLast unsuccessful login: Tue Jul  7 03:04:50 BEIST 2020 on ssh from 192.168.0.5\r\nLast login: Tue Jul  7 15:18:11 BEIST 2020 on ssh from 192.168.0.4\r\nWelcome!\r\n/etc/profile[63]: hostname:  not found.\r\n" (spawn_id exp4) match regular expression "^:.*$"? Gate ":*"? gate=yes re=no
"send_user"? no
:/home/padmin$ 
expect: does " \r\nLast unsuccessful login: Tue Jul  7 03:04:50 BEIST 2020 on ssh from 192.168.0.5\r\nLast login: Tue Jul  7 15:18:11 BEIST 2020 on ssh from 192.168.0.4\r\nWelcome!\r\n/etc/profile[63]: hostname:  not found.\r\n:/home/padmin$ " (spawn_id exp4) match regular expression "^:.*$"? Gate ":*"? gate=yes re=no
"send_user"? no
expect: timed out
Gate keeper glob pattern for '^:.*$' is ':*'. Activating booster.

expect: does " \r\nLast unsuccessful login: Tue Jul  7 03:04:50 BEIST 2020 on ssh from 192.168.0.5\r\nLast login: Tue Jul  7 15:18:11 BEIST 2020 on ssh from 192.168.0.4\r\nWelcome!\r\n/etc/profile[63]: hostname:  not found.\r\n:/home/padmin$ " (spawn_id exp4) match regular expression "^:.*$"? Gate ":*"? gate=yes re=no
sighandler: handling signal(2)
async event handler: Tcl_Eval(exit 130)

那么我该如何解决该问题呢？非常感谢。