如何记录 ssh 调试信息？

Question

I need to write the output of ssh debug info into the file. This

ssh -v root@172.16.248.xx > result.txt
ssh -v root@172.16.248.xx 2>&1 > result.txt

doesn't work, the file result.txt is empty, but on the screen i see bunch of debug lines, like:

OpenSSH_5.3p1 Debian-3ubuntu7, OpenSSL 0.9.8k 25 Mar 2009
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to 172.16.248.xx [172.16.248.xx] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
etc

Is there a way to redirect these lines to the file?

Answer 1

You have to change the order of the redirections on the command line:

ssh -v root@172.16.248.xx >result.txt 2>&1

or just:

ssh -v root@172.16.248.xx 2>result.txt

Answer 2

 -E log_file
         Append debug logs to log_file instead of standard error.

Answer 3

显然，将此“隐藏”调试输出保存到文件的最佳方法是使用 logsave：

logsave result.txt ssh -v root@172.16.248.xx