如何使用expect发送变量加字符串

Question

set user [lindex $argv 0]
expect ">" {send "passwd $user\r"}
sleep 1

尝试发送变量和字符串 01 以生成密码，如果用户变量类似于 Samanta 我应该发送 Samanta01

expect "UNIX" {send $user"01\r"}
sleep 1
expect "UNIX" {send $user"01\r"}

我也尝试发送为：

expect "UNIX" {send "$user"01\r""}
and as
expect "UNIX" {send "$user'01\r'"}