Is it possible to spawn an ssh-agent for a new tmux session?

Question

I've seen lots of hacks for re-establishing contact with a GUI session's SSH agent from within tmux (and screen) sessions. I'm wondering if it's possible to de-couple from the GUI and spawn an ssh-agent purely for use within a given tmux session? Would the agent itself have to "use-up" one of the tmux windows to avoid getting killed or is it possible to spawn one in the background that persists as long as the session is alive?

Dup of http://superuser.com/q/237822/46794? – Blaisorblade Sep 19 '13 at 08:30 — Blaisorblade, Sep 19 '13 at 08:30

score 3 · Accepted Answer · edited Sep 26 '12 at 13:59

OK I've done some more digging around and I should be able to easily hook to whatever SSH_AGENT is around when the terminal is attached. tmux already provides the key configuration "update-environment" however the missing piece is existing shells are not magically updated. However tmux does track the environment variables updated so the update script is a lot less hacky than screens:


# Sync the environment of an existing shell
#
#  tmux already updates the environment according to
#  the update-environment settings in the config. However
#  for existing shells you need to sync from from tmux's view
#  of the world.
function tmux_sync_env
{
    external_env=`tmux showenv | grep -v "^-"`
    export ${external_env}
}

From this commit

@Thor: I was wondering what was going on, I think the editor was inserting a space because the link was so long... — stsquad, Sep 26 '12 at 16:16

score 2 · Answer 2 · edited Mar 20 '17 at 10:16

2

I had to modify @stsquad's answer. It was failing for me because the export command could not set the SSH_CONNECTION variable.

I had to wrap the value of SSH_CONNECTION in quotes.

function tmux_sync_env
{
    ssh_auth_sock=`tmux showenv | grep "^SSH_AUTH_SOCK"`
    ssh_connection=`tmux showenv | grep "^SSH_CONNECTION"`
    export ${ssh_auth_sock}
    export "${ssh_connection}"
}

edited Mar 20 '17 at 10:16

Community

1

answered Mar 26 '15 at 21:09

Christian Long

1,741
16
9

score 0 · Answer 3 · answered May 10 '13 at 17:15

0

Another option I've found recently is Daniel Robbins' keychain utility which offers a neat way to reconnect and have a user/host wide agent instead of just a session wide one.

answered May 10 '13 at 17:15

stsquad

499
5
19

Is it possible to spawn an ssh-agent for a new tmux session?

3 Answers3

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