tmux.pane_movements

This shard provides four executables for directional pane navigation:

• to-left-pane
• to-lower-pane
• to-right-pane
• to-upper-pane

Build them with:

bundle exec rake

Bind them to Alt+H/J/K/L in tmux:

bind -n M-h run-shell "to-left-pane"
bind -n M-j run-shell "to-lower-pane"
bind -n M-k run-shell "to-upper-pane"
bind -n M-l run-shell "to-right-pane"

When the target window has more than one pane, an executable selects the adjacent tmux pane. When it has only one pane, it sends C-w followed by h, j, k, or l only when the foreground command is vim or nvim. For every other application, it forwards the matching Alt chord (M-h, M-j, M-k, or M-l) into the pane.

The target pane comes from TMUX_PANE; when that variable is unavailable, the executable asks tmux for its current pane. Pane metadata and key commands are explicitly targeted at that pane, so the pane count is scoped to its window rather than relying on tmux's implicit default target.

When the foreground command is tmux.repl.input, the lower and upper bindings forward Alt+J/K to the input process even in a multi-pane window. This lets the REPL use those keys as input-selection aliases without breaking pane movement for other applications.