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#title: The definitive guide to using tmux-256color on macOS date: 2021-04-14 tags: [tmux, macos, terminal]

macOS ships with an old and very out-of-date version of ncurses (5.7). This version does not contain a terminfo entry for tmux-256color, the preferred TERM value when using tmux.

If you installed tmux via Homebrew or MacPorts, then you will also have a newer version of ncurses (6.2) present on your system installed by your package manager. This is the version of ncurses that tmux itself was built against, which is why you can use

set -s default-terminal tmux-256color

in your .tmux.conf without any errors. However, as soon as you try to use any application linked against macOS's version of ncurses (such as man or ls -G), you will notice that things no longer work.

The solution is to get the tmux-256color terminfo entry from the newer version of ncurses into macOS's terminfo database. First, create a copy of the current tmux-256color terminfo entry from the version of curses installed by your package manager:

# MacPorts
$ /opt/local/bin/infocmp -x tmux-256color > ~/tmux-256color.src

# Homebrew
$ /usr/local/opt/ncurses/bin/infocmp -x tmux-256color > ~/tmux-256color.src

Now, modify the tmux-256color.src file to change the pairs value from 65536 to 32768. This must be done because of a bug in ncurses 5.7 that interprets pairs#65536 as pairs#0[^1].









If your are on a macOS version prior to Catalina, you can install this new terminfo entry into the system database /usr/share/terminfo. This will ensure that programs linked against the old version of ncurses will use this entry, while programs installed by your package manager will continue to use the entry from the newer version of ncurses. To do this, simply run

$ sudo /usr/bin/tic -x tmux-256color.src

Be sure to use /usr/bin/tic and not just tic: this will use the system version of ncurses to compile the database entry, which is required for system programs linked against that version of ncurses work properly.

Unfortunately, if you are on Catalina or later this will not work since the root volume (of which /usr/share/terminfo is a part) is read-only. There are, apparently, workarounds to make the root volume writable, so if you want to go that route you can. Otherwise, simply run the command above without sudo:

$ /usr/bin/tic -x tmux-256color.src

This will install the terminfo database entry under $HOME/.terminfo. This will still work; however, now all programs on your machine will use this terminfo database entry, even if they were linked against the fully functional 6.2 version of ncurses provided by your package manager. This is an unfortunate tradeoff, but as of this writing I don't know any way around it.

After that, you should be able to correcty use tmux-256color as your TERM variable. You can check that everything is working by running a few programs that make use of ncurses and terminal colors, such as htop, man, ls -G, etc.

[^1]: See Thomas Dickey's comment here.