Tente o seguinte:
bind-key -T copy-mode M-w send-keys -X copy-pipe 'reattach-to-user-namespace pbcopy'
Observe que tmux
alterou recentemente as tabelas principais :
Key tables have undergone major changes. Mode key tables are no longer separate from the main key tables. All mode key tables have been removed, together with the -t flag to bind-key and unbind-key.
The emacs-edit, vi-edit, emacs-choose and vi-choose tables have been replaced by fixed key bindings in the command prompt and choose modes. The mode-keys and status-keys options remain.
The emacs-copy and vi-copy tables have been replaced by the copy-mode and copy-mode-vi tables. Commands are sent using the -X and -N flags to send-keys. So the following:
bind -temacs-copy C-Up scroll-up bind -temacs-copy -R5 WheelUpPane scroll-up
Becomes:
bind -Tcopy-mode C-Up send -X scroll-up bind -Tcopy-mode WheelUpPane send -N5 -X scroll-up
This changes allows the full command parser (including command sequences) and command set to be used - for example, the normal command prompt with editing and history is now used for searching, jumping, and so on instead of a custom one. The default C-r binding is now:
bind -Tcopy-mode C-r command-prompt -p'search up' "send -X search-backward '%%'"
There are also some new commmands available with send -X, such as
copy-pipe-and-cancel.