~/.tmux.conf doesn't work when starting but does with "source-file"

Question

I want to start tmux with two panes and have one of them running a program:

[0] [ishpeck@kiyoshi ~]$ cat ~/.tmux.conf
split-window -h top
[0][ishpeck@kiyoshi ~]$ tmux

When tmux comes up, it displays the error:

/home/ishpeck/.tmux.conf:1: no current target

With tmux still open, I hit prefix then type ":source ~/.tmux.conf " and it works as expected. Why does it never work at start-up, but works fine when I'm sourcing it?

Answer 1

I figured out a solution that only involves tmux but still involves a second file.

In your tmux.conf add this line:

set-hook -g after-new-session "source-file /path/to/tmux-windows.conf"

Then put your windows and splits in that tmux-windows.conf file.

Answer 2

Having now looked at the code for tmux, it appears that the config file is read before there is any session. It's not a trivial to change that.

Based on the comments from Aulis Ronkainen, it looks like the best bet is to have a shell script that runs tmux commands.

See also: https://www.reddit.com/r/linuxquestions/comments/82yi3s/how_to_get_tmux_to_start_with_a_couple_of_split/