How to rename a pane in tmux?

Question

Do you mean tmux window? Ctrl + b + , if you have C-b as send prefix (it's by default)

Also C-b :rename-window <new name> and tmux rename-window <new name> work too.

As I know you can't rename pane

yes you can rename pane names, and not only window names starting with tmux >= 2.3. Just type the following in your shell:

printf '\033]2;%s\033\\' 'title goes here'

you might need to add the following to your .tmux.conf to display pane names:

# Enable names for panes
set -g pane-border-status top

you can also automatically assign a name:

set -g pane-border-format "#P: #{pane_current_command}"

For those scripting tmux, there is a command called rename-window so e.g.

tmux rename-window -t <window> <newname>

For those who want to easily rename their panes, this is what I have in my .tmux.conf

set -g default-command '                      \
function renamePane () {                      \
  read -p "Enter Pane Name: " pane_name;      \
  printf "\033]2;%s\033\\r:r" "${pane_name}"; \
};                                            \
export -f renamePane;                         \
bash -i'
set -g pane-border-status top
set -g pane-border-format "#{pane_index} #T #{pane_current_command}"
bind-key -T prefix R send-keys "renamePane" C-m

Panes are automatically named with their index, machine name and current command. To change the machine name you can run <C-b>R which will prompt you to enter a new name.

*Pane renaming only works when you are in a shell.

Also when scripting, you can specify a name when creating the window with -n <window name>. For example:

# variable to store the session name
SESSION="my_session"

# set up session
tmux -2 new-session -d -s $SESSION

# create window; split into panes
tmux new-window -t $SESSION:0 -n 'My Window with a Name'

The easiest option for me was to rename the title of the terminal instead. Please see: https://superuser.com/questions/362227/how-to-change-the-title-of-the-mintty-window

In this answer, they mention to modify the PS1 variable. Note: my situation was particular to cygwin.

TL;DR Put this in your .bashrc file:

function settitle() {
      export PS1="\[\e[32m\]\u@\h \[\e[33m\]\w\[\e[0m\]\n$ "
      echo -ne "\e]0;$1\a"
}

Put this in your .tmux.conf file, or similar formatting:

set -g pane-border-status bottom
set -g pane-border-format "#P #T #{pane_current_command}"

Then you can change the title of the pane by typing this in the console:

settitle titlename

You can adjust the pane title by setting the pane border in the tmux.conf for example like this:

###############
# pane border #
###############
set -g pane-border-status bottom
#colors for pane borders
setw -g pane-border-style fg=green,bg=black
setw -g pane-active-border-style fg=colour118,bg=black
setw -g automatic-rename off
setw -g pane-border-format ' #{pane_index} #{pane_title} : #{pane_current_path} '
# active pane normal, other shaded out​
setw -g window-style fg=colour28,bg=colour16
setw -g window-active-style fg=colour46,bg=colour16

Where pane_index, pane_title and pane_current_path are variables provided by tmux itself.

After reloading the config or starting a new tmux session, you can then set the title of the current pane like this:

tmux select-pane -T "fancy pane title";
#or
tmux select-pane -t paneIndexInteger -T "fancy pane title";

If all panes have some processes running, so you can't use the command line, you can also type the commands after pressing the prefix bind (C-b by default) and a colon (:) without having "tmux" in the front of the command:

select-pane -T "fancy pane title"
#or:
select-pane -t paneIndexInteger -T "fancy pane title"