014 调试SSH客户端会话

有时候我们需要打印调试信息来查找SSH客户端出现的问题。将参数-v(小写的v)传给ssh命令就可以显示调试信息。
以下是不包含调试信息的例子：

localhost$ ssh -l jsmith remotehost.example.com 
 
warning: Connecting to remotehost.example.com failed: 
No address associated to the name

以下是包含调试信息的例子：

locaclhost$ ssh -v -l jsmith remotehost.example.com 
 
debug: 
SshConfig/sshconfig.c:2838/ssh2_parse_config_ext: 
Metaconfig parsing stopped at line 3. 
 
debug: 
SshConfig/sshconfig.c:637/ssh_config_set_param_verbose: 
Setting variable 'VerboseMode’ to 'FALSE’. 
 
debug: 
SshConfig/sshconfig.c:3130/ssh_config_read_file_ext: 
Read 17 params from config file. 
 
debug: Ssh2/ssh2.c:1707/main: User config file not 
found, using defaults. (Looked for 
'/home/jsmith/.ssh2/ssh2_config’) 
 
debug: Connecting to remotehost.example.com, port 22… 
(SOCKS not used) 
warning: Connecting to remotehost.example.com failed: 
No address associated to the name