bash - 从此处开始的 SSH session Doc 未正确退出

Question

SSH session 在 here 文档中执行时不会终止并返回 tty。下面是我的 shell 脚本中的代码片段:

ssh -t -t root@$HOST_ADDRESS <<TERM_STRING
cd /tmp/
sleep 2
exit 0
TERM_STRING

命令 exit 0 后，终端卡住了，没有给我返回 tty。我做错了什么吗？

这是我在使用 -v 标志尝试 SSH 后得到的结果

[root ~]# ssh -v -t -t 10.215.194.38
OpenSSH_4.3p2, OpenSSL 0.9.8e-fips-rhel5 01 Jul 2008
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to 10.215.194.38 [10.215.194.38] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: identity file /root/.ssh/identity type -1
debug1: identity file /root/.ssh/id_rsa type 1
debug1: identity file /root/.ssh/id_dsa type -1
debug1: loaded 3 keys
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.2
debug1: match: OpenSSH_5.2 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_4.3
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-cbc hmac-md5 none
debug1: kex: client->server aes128-cbc hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Host '10.215.194.38' is known and matches the RSA host key.
debug1: Found key in /root/.ssh/known_hosts:5
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received

debug1: Authentications that can continue: publickey,gssapi-with-mic,password
debug1: Next authentication method: gssapi-with-mic
debug1: Unspecified GSS failure.  Minor code may provide more information
Unknown code krb5 195

debug1: Unspecified GSS failure.  Minor code may provide more information
Unknown code krb5 195

debug1: Unspecified GSS failure.  Minor code may provide more information
Unknown code krb5 195

debug1: Next authentication method: publickey
debug1: Trying private key: /root/.ssh/identity
debug1: Offering public key: /root/.ssh/id_rsa
debug1: Server accepts key: pkalg ssh-rsa blen 277
debug1: read PEM private key done: type RSA
debug1: Authentication succeeded (publickey).
debug1: channel 0: new [client-session]
debug1: Entering interactive session.
debug1: Sending environment.
debug1: Sending env LANG = en_US

Last login: Wed Jan 23 14:02:39 2013 from 10.134.232.195
[root@10.215.194.38 ~]# exit 0

唯一让我印象深刻的是这句话:

debug1: Next authentication method: gssapi-with-mic
debug1: Unspecified GSS failure.  Minor code may provide more information
Unknown code krb5 195

Answer 1

刚刚在我的服务器上试过，它可以工作(Ubuntu 连接到 Centos 6)。

尝试在服务器配置中禁用 GSSAPI(将其注释掉并重新启动 sshd，您不会丢失连接)

如果连接挂起试试这个:

1. 查看ssh进程的PID
2. 查看/proc/下的提示
3. 查看 lsof 并查看 ssh 是否保持任何打开状态
4. 检查客户端是否配置为自动设置端口转发

问候 亚历山德罗