Last Updated: May 08, 2017
· bloy

Fix SSH agent in reattached tmux session shells

A new remote logon session creates a different SSHAUTHSOCK and friends. This can be a problem if existing shells in a detached tmux session retain the old ssh-agent environment variables; github pushes and pulls won't work, ssh to other machines will have trouble, etc

Add this function to your shell (works for zsh, I think it will work in bash), and run "fixssh" in each shell that needs to communicate with ssh-agent:

fixssh() {
    if (tmux show-environment | grep "^${key}" > /dev/null); then
      value=`tmux show-environment | grep "^${key}" | sed -e "s/^[A-Z_]*=//"`
      export ${key}="${value}"

EDIT, much later: The following gist lays out a more automatic way of solving this problem:

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Thank you Mike, you kinda solved my problem, now the last part to solve is how to auto-repair this without changing anything on the remote host?

On my computer I customized SSH so it does always try to restore the last tmux session when I ssh a machine - works pretty well but as you noted bad things happen.

I do not want to have to "prepare" all machines so I need a solution from the client SSH client... it seems that the connect code will become more complex now..

over 1 year ago ·