tmux
I've tinkered with tmux and have seen settings that would highlight the border of the active pane. This works fine for three or more panes.
However, my most common usage would be two panes side by side, and none of the border highlighting I've seen helps me tell which is active if there are only two.
What setting can I give tmux to make it clear which of two panes is focused?
This issue is resolved in the current version of tmux. When there are only two splits the upper/lower half of the split line is colored to indicate that the left/right split is active
This is what is happening:
tmux new 'tmux source-file ~/.tmux/dev'
The new commands creates a new session with a single window that has a single pane. The command tmux source-file ~/.tmux/dev runs in this new pane.
N (where N is some number), withN:0 (or whatever you have base-index set to), withN:0.0 (or whatever you have base-pane-index set to),tmux source-file ~/.tmux/dev.The source-file command is processed.
send-keys command then “types” vim . + Enter at pane 0.source-file command.So the unexpected bit is that pane 0 (i.e. N:0.0) is running (only) the source-file command which ignores your “typed” command. This pane never runs an interactive shell that could interpret the “typed” command.
There are at least a couple of ways you can fix this:
Start ~/.tmux/dev with new-window so that pane 0 is running your “default command” (i.e. probably an interactive shell).
This method has the benefit of not assuming that your current pane is running an interactive shell, and also not assuming that the current pane is 0 (i.e. what happens if you run your original series of commands against a pane that is part of an already split window?). It means you can safely bind source-file ~/.tmux/dev to a key that you can run in any context (since it creates a new window for all of its panes). From the shell you can run either tmux source-file ~/.tmux/dev (to create a new window in the current session), or your original tmux new 'tmux source-file ~/.tmux/dev' to create a new session.
A minor drawback to this method is that when you run tmux new 'tmux source-file ~/.tmux/dev', the initial window will still run the client that sends source-file and exit fairly quickly. This means that your “main window” (the one with the splits) will be one higher than your base-index and a future new window will be placed before the “main window”. You could fix this by using something like this:
tmux new 'tmux move-window -t 99 \; source-file ~/.tmux/dev'
It moves the (ephemeral) initial window to a high index so that the new-window in ~/.tmux/dev will end up at base-index.
Use (e.g.) tmux new 'tmux source-file ~/.tmux/dev ; zsh -l' so that the pane ends up running an interactive shell after the source-file command finishes.
The ugly bit about this is that you end up “hard coding” your preferred shell into this command. Also, the send-keys input (vim . + Enter) is technically sent before the shell starts; this is probably okay, but may not always be completely reliable.
You could avoid “hard coding” your shell by querying tmux for the default-command (or if that is not set, default-shell (or if that is not set, using SHELL)), but that may be more work than you really want to do.
Best Answer
Use Tmux 1.8
Starting in tmux 1.8, tmux distinguishes between a left/right active pane by only highlighting the top/bottom half of the split line.
Screenshot (iTerm2 + tmux 1.8):
If you must use an earlier version, none of the tmux settings appear to help in your exact case. As an alternative, you could look for the blinking shell cursor, which only appears in the active pane.