Every time I start tmux or split tmux, new instance of ssh-agent is started ("Agent pid XXXX" appears on the top), which is quite annoying because I have to type the key password every time I want to use it. Not to mention the number of ssh-agents at the end of the day.

I'm using Arch Linux with KDE and my $SHELL is zshell.

ssh-agent starts automatically on system boot, but I can't figure out who starts it - it's not in the .zshrc or .bash_profile, I've tried to grep for 'ssh-agent' in the ~but found nothing.

  • Does your .zshrc or .profile source any files in /etc?
    – Barmar
    Jan 20, 2015 at 20:32
  • No, it doesn't. Jan 20, 2015 at 20:36

1 Answer 1


By default, tmux spawns a login shell for all new windows. This would then source your ~/.zprofile or wherever your start your ssh-agent.

As man tmux makes clear, you can avoid this behaviour by explicitly setting a default command in your ~/.tmux.conf:

default-command shell-command
Set the command used for new windows (if not specified when the window is created) to shell-command, which may be any sh(1) command. The default is an empty string, which instructs tmux to create a login shell using the value of the default-shell option.

So, to prevent every new window being spawned as a login shell, add the following line to your config file:

set -g default-command /bin/zsh
  • I should have read the man page, thank you, it works :) Jan 21, 2015 at 8:23
  • @nacholibre I thought you said none of your scripts in ~ ran ssh-agent. Did you miss .zprofile?
    – Barmar
    Jan 21, 2015 at 17:26

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