exp_send在ssh之后无法正常工作

Question

我创建了2个tcl文件，login.tcl和x.tcl，预计在ssh之后将pwd命令发送到服务器，但是它不起作用。 x.tcl中的脚本如下所示。

package require Expect
source ./login.tcl
set ipaddr 172.19.3.4
set passwd 123456
exp_internal 1
global g_prompt
global g_pwd_prompt
set g_prompt #
set g_pwd_prompt password
set loginName root@$ipaddr
set spawnid_test [login $loginName $passwd]
if {$spawnid_test == -1} {
   puts "ssh failed, exit!\n"
   exit 1
} else {
    exp_send -i $spawnid_test "pwd\n"
}

输出结果为：

[jeff@jeff ~]$ tclsh x.tcl
spawn ssh root@172.19.3.4
parent: waiting for sync byte
parent: telling child to go ahead
parent: now unsynchronized from child
spawn: returns {31879}

expect: does "" (spawn_id exp6) match glob pattern "yes/no"? no
"password"? no
"#"? no
"Connection refused"? no
root@172.19.3.4's password: 
expect: does "root@172.19.3.4's password: " (spawn_id exp6) match 
glob pattern "yes/no"? no
"password"? yes
expect: set expect_out(0,string) "password"
expect: set expect_out(spawn_id) "exp6"
expect: set expect_out(buffer) "root@172.19.3.4's password"
send: sending "123456\n" to { exp6 }
expect: continuing expect

expect: does ": " (spawn_id exp6) match glob pattern "yes/no"? no
"password"? no
"#"? no
"Connection refused"? no


expect: does ": \r\n" (spawn_id exp6) match glob pattern "yes/no"? no
"password"? no
"#"? no
"Connection refused"? no
Last login: Sun May  4 12:59:35 2014 from 172.19.3.3

expect: does ": \r\nLast login: Sun May  4 12:59:35 2014 from 172.19.3.3
\r\r\n"(spawn_id exp6) match glob pattern "yes/no"? no
"password"? no
"#"? no
"Connection refused"? no

expect: does ": \r\nLast login: Sun May  4 12:59:35 2014 
from 172.19.3.3\r\r\n\u001b]0;root@172.19.3.4:~\u0007" (spawn_id exp6) match glob 
pattern "yes/no"? no
"password"? no
"#"? no
"Connection refused"? no
[root@172.19.3.4 ~]# 
expect: does ": \r\nLast login: Sun May  4 12:59:35 2014
from 172.19.3.3\r\r\n\u001b]0;root@172.19.3.4:~\u0007[root@172.19.3.4 ~]# " (spawn_id 
exp6) match glob pattern "yes/no"? no
"password"? no
"#"? yes
expect: set expect_out(0,string) "#"
expect: set expect_out(spawn_id) "exp6"
expect: set expect_out(buffer) ": \r\nLast login: Sun May  4 12:59:35 2014 
from 172.19.3.3\r\r\n\u001b]0;root@172.19.3.4:~\u0007[root@172.19.3.4 ~]#"
login successful, spawn_id = exp6

send: sending "pwd\n" to { exp6 }

从日志中，问题是为什么＆＃34;发送：发送＆＃34; 123456 \ n＆＃34;至{exp6}＆＃34;有效，但是＆＃34;发送：发送＆＃34; pwd \ n＆＃34;至{exp6}＆＃34;不？