TMUX(1) General Commands Manual TMUX(1)

tmux —
terminal multiplexer

tmux [-28lquv] [-c shell-command] [-f file] [-L socket-name] [-S socket-path] [command [flags]]

tmux is a terminal multiplexer: it enables a number of terminals to be created, accessed, and controlled from a single screen. tmux may be detached from a screen and continue running in the background, then later reattached.

When tmux is started it creates a new session with a single window and displays it on screen. A status line at the bottom of the screen shows information on the current session and is used to enter interactive commands.

A session is a single collection of pseudo terminals under the management of tmux. Each session has one or more windows linked to it. A window occupies the entire screen and may be split into rectangular panes, each of which is a separate pseudo terminal (the pty(4) manual page documents the technical details of pseudo terminals). Any number of tmux instances may connect to the same session, and any number of windows may be present in the same session. Once all sessions are killed, tmux exits.

Each session is persistent and will survive accidental disconnection (such as ssh(1) connection timeout) or intentional detaching (with the ‘C-b d’ key strokes). tmux may be reattached using:

$ tmux attach

In tmux, a session is displayed on screen by a client and all sessions are managed by a single server. The server and each client are separate processes which communicate through a socket in /tmp.

The options are as follows:

Force tmux to assume the terminal supports 256 colours.
Like -2, but indicates that the terminal supports 88 colours.
shell-command
Execute shell-command using the default shell. If necessary, the tmux server will be started to retrieve the default-shell option. This option is for compatibility with sh(1) when tmux is used as a login shell.
file
Specify an alternative configuration file. By default, tmux loads the system configuration file from /etc/tmux.conf, if present, then looks for a user configuration file at ~/.tmux.conf. The configuration file is a set of tmux commands which are executed in sequence when the server is first started.

If a command in the configuration file fails, tmux will report an error and exit without executing further commands.

socket-name
tmux stores the server socket in a directory under /tmp; the default socket is named default. This option allows a different socket name to be specified, allowing several independent tmux servers to be run. Unlike -S a full path is not necessary: the sockets are all created in the same directory.

If the socket is accidentally removed, the SIGUSR1 signal may be sent to the tmux server process to recreate it.

Behave as a login shell. This flag currently has no effect and is for compatibility with other shells when using tmux as a login shell.
Set the quiet server option to prevent the server sending various informational messages.
socket-path
Specify a full alternative path to the server socket. If -S is specified, the default socket directory is not used and any -L flag is ignored.
tmux attempts to guess if the terminal is likely to support UTF-8 by checking the first of the LC_ALL, LC_CTYPE and LANG environment variables to be set for the string "UTF-8". This is not always correct: the -u flag explicitly informs tmux that UTF-8 is supported.

If the server is started from a client passed -u or where UTF-8 is detected, the utf8 and status-utf8 options are enabled in the global window and session options respectively.

Request verbose logging. This option may be specified multiple times for increasing verbosity. Log messages will be saved into tmux-client-PID.log and tmux-server-PID.log files in the current directory, where PID is the PID of the server or client process.
command [flags]
This specifies one of a set of commands used to control tmux, as described in the following sections. If no commands are specified, the new-session command is assumed.

tmux may be controlled from an attached client by using a key combination of a prefix key, ‘C-b’ (Ctrl-b) by default, followed by a command key.

The default command key bindings are:

C-b
Send the prefix key (C-b) through to the application.
C-o
Rotate the panes in the current window forwards.
C-z
Suspend the tmux client.
!
Break the current pane out of the window.
"
Split the current pane into two, top and bottom.
#
List all paste buffers.
%
Split the current pane into two, left and right.
&
Kill the current window.
'
Prompt for a window index to select.
,
Rename the current window.
-
Delete the most recently copied buffer of text.
.
Prompt for an index to move the current window.
0 to 9
Select windows 0 to 9.
:
Enter the tmux command prompt.
;
Move to the previously active pane.
=
Choose which buffer to paste interactively from a list.
?
List all key bindings.
D
Choose a client to detach.
[
Enter copy mode to copy text or view the history.
]
Paste the most recently copied buffer of text.
c
Create a new window.
d
Detach the current client.
f
Prompt to search for text in open windows.
i
Display some information about the current window.
l
Move to the previously selected window.
n
Change to the next window.
o
Select the next pane in the current window.
p
Change to the previous window.
q
Briefly display pane indexes.
r
Force redraw of the attached client.
s
Select a new session for the attached client interactively.
L
Switch the attached client back to the last session.
t
Show the time.
w
Choose the current window interactively.
x
Kill the current pane.
{
Swap the current pane with the previous pane.
}
Swap the current pane with the next pane.
~
Show previous messages from tmux, if any.
Page Up
Enter copy mode and scroll one page up.
Up, Down
 
Left, Right
Change to the pane above, below, to the left, or to the right of the current pane.
M-1 to M-5
Arrange panes in one of the five preset layouts: even-horizontal, even-vertical, main-horizontal, main-vertical, or tiled.
M-n
Move to the next window with a bell or activity marker.
M-o
Rotate the panes in the current window backwards.
M-p
Move to the previous window with a bell or activity marker.
C-Up, C-Down
 
C-Left, C-Right
Resize the current pane in steps of one cell.
M-Up, M-Down
 
M-Left, M-Right
Resize the current pane in steps of five cells.

Key bindings may be changed with the bind-key and unbind-key commands.

This section contains a list of the commands supported by tmux. Most commands accept the optional -t argument with one of target-client, target-session target-window, or target-pane. These specify the client, session, window or pane which a command should affect. target-client is the name of the pty(4) file to which the client is connected, for example either of /dev/ttyp1 or ttyp1 for the client attached to /dev/ttyp1. If no client is specified, the current client is chosen, if possible, or an error is reported. Clients may be listed with the list-clients command.

target-session is either the name of a session (as listed by the list-sessions command) or the name of a client with the same syntax as target-client, in which case the session attached to the client is used. When looking for the session name, tmux initially searches for an exact match; if none is found, the session names are checked for any for which target-session is a prefix or for which it matches as an fnmatch(3) pattern. If a single match is found, it is used as the target session; multiple matches produce an error. If a session is omitted, the current session is used if available; if no current session is available, the most recently used is chosen.

target-window specifies a window in the form session:window. session follows the same rules as for target-session, and window is looked for in order: as a window index, for example mysession:1; as an exact window name, such as mysession:mywindow; then as an fnmatch(3) pattern or the start of a window name, such as mysession:mywin* or mysession:mywin. An empty window name specifies the next unused index if appropriate (for example the new-window and link-window commands) otherwise the current window in session is chosen. The special character ‘!’ uses the last (previously current) window, or ‘+’ and ‘-’ are the next window or the previous window by number. When the argument does not contain a colon, tmux first attempts to parse it as window; if that fails, an attempt is made to match a session.

target-pane takes a similar form to target-window but with the optional addition of a period followed by a pane index, for example: mysession:mywindow.1. If the pane index is omitted, the currently active pane in the specified window is used. If neither a colon nor period appears, tmux first attempts to use the argument as a pane index; if that fails, it is looked up as for target-window. A ‘+’ or ‘-’ indicate the next or previous pane index, respectively. One of the strings top, bottom, left, right, top-left, top-right, bottom-left or bottom-right may be used instead of a pane index.

The special characters ‘+’ and ‘-’ may be followed by an offset, for example:

select-window -t:+2

When dealing with a session that doesn't contain sequential window indexes, they will be correctly skipped.

shell-command arguments are sh(1) commands. These must be passed as a single item, which typically means quoting them, for example:

new-window 'vi /etc/passwd'

command [arguments] refers to a tmux command, passed with the command and arguments separately, for example:

bind-key F1 set-window-option force-width 81

Or if using sh(1):

$ tmux bind-key F1 set-window-option force-width 81

Multiple commands may be specified together as part of a command sequence. Each command should be separated by spaces and a semicolon; commands are executed sequentially from left to right. A literal semicolon may be included by escaping it with a backslash (for example, when specifying a command sequence to bind-key).

Example tmux commands include:

refresh-client -t/dev/ttyp2

rename-session -tfirst newname

set-window-option -t:0 monitor-activity on

new-window ; split-window -d

Or from sh(1):

$ tmux kill-window -t :1

$ tmux new-window \; split-window -d

$ tmux new-session -d 'vi /etc/passwd' \; split-window -d \; attach

The tmux server manages clients, sessions, windows and panes. Clients are attached to sessions to interact with them, either when they are created with the new-session command, or later with the attach-session command. Each session has one or more windows linked into it. Windows may be linked to multiple sessions and are made up of one or more panes, each of which contains a pseudo terminal. Commands for creating, linking and otherwise manipulating windows are covered in the WINDOWS AND PANES section.

The following commands are available to manage clients and sessions:

[-dr] [-t target-session]
(alias: attach)
If run from outside tmux, create a new client in the current terminal and attach it to target-session. If used from inside, switch the current client. If -d is specified, any other clients attached to the session are detached. -r signifies the client is read-only (only keys bound to the detach-client command have any effect)

If no server is started, attach-session will attempt to start it; this will fail unless sessions are created in the configuration file.

[-t target-client]
(alias: detach)
Detach the current client if bound to a key, or the specified client with -t.
[-t target-session]
(alias: has)
Report an error and exit with 1 if the specified session does not exist. If it does exist, exit with 0.
Kill the tmux server and clients and destroy all sessions.
[-t target-session]
Destroy the given session, closing any windows linked to it and no other sessions, and detaching all clients attached to it.
(alias: lsc)
List all clients attached to the server.
(alias: lscm)
List the syntax of all commands supported by tmux.
(alias: ls)
List all sessions managed by the server.
[-t target-client]
(alias: lockc)
Lock target-client, see the lock-server command.
[-t target-session]
(alias: locks)
Lock all clients attached to target-session.
[-d] [-n window-name] [-s session-name] [-t target-session] [shell-command]
(alias: new)
Create a new session with name session-name.

The new session is attached to the current terminal unless -d is given. window-name and shell-command are the name of and shell command to execute in the initial window.

If run from a terminal, any termios(4) special characters are saved and used for new windows in the new session.

If -t is given, the new session is grouped with target-session. This means they share the same set of windows - all windows from target-session are linked to the new session and any subsequent new windows or windows being closed are applied to both sessions. The current and previous window and any session options remain independent and either session may be killed without affecting the other. Giving -n or shell-command are invalid if -t is used.

[-t target-client]
(alias: refresh)
Refresh the current client if bound to a key, or a single client if one is given with -t.
[-t target-session] new-name
(alias: rename)
Rename the session to new-name.
[-t target-client]
(alias: showmsgs)
Any messages displayed on the status line are saved in a per-client message log, up to a maximum of the limit set by the message-limit session option for the session attached to that client. This command displays the log for target-client.
path
(alias: source)
Execute commands from path.
(alias: start)
Start the tmux server, if not already running, without creating any sessions.
[-t target-client]
(alias: suspendc)
Suspend a client by sending SIGTSTP (tty stop).
[-lnp] [-c target-client] [-t target-session]
(alias: switchc)
Switch the current session for client target-client to target-session. If -l, -n or -p is used, the client is moved to the last, next or previous session respectively.

A tmux window may be in one of several modes. The default permits direct access to the terminal attached to the window. The other is copy mode, which permits a section of a window or its history to be copied to a paste buffer for later insertion into another window. This mode is entered with the copy-mode command, bound to ‘[’ by default. It is also entered when a command that produces output, such as list-keys, is executed from a key binding.

The keys available depend on whether emacs or vi mode is selected (see the mode-keys option). The following keys are supported as appropriate for the mode:

Function vi emacs
^ M-m
G M-<
Escape C-g
Enter M-w
j Down
h Left
l Right
L
M M-r
H M-R
k Up
d C-u
D C-k
$ C-e
: g
C-d M-Down
C-u M-Up
f f
F F
; ;
, ,
C-f Page down
W
E
w
e M-f
p C-y
C-b Page up
b M-b
B
q Escape
v R
C-Down or C-e C-Down
C-Up or C-y C-Up
n n
N N
? C-r
/ C-s
0 C-a
Space C-Space
g M->
C-t

The next and previous word keys use space and the ‘-’, ‘_’ and ‘@’ characters as word delimiters by default, but this can be adjusted by setting the word-separators window option. Next word moves to the start of the next word, next word end to the end of the next word and previous word to the start of the previous word. The three next and previous space keys work similarly but use a space alone as the word separator.

The jump commands enable quick movement within a line. For instance, typing ‘f’ followed by ‘/’ will move the cursor to the next ‘/’ character on the current line. A ‘;’ will then jump to the next occurrence.

Commands in copy mode may be prefaced by an optional repeat count. With vi key bindings, a prefix is entered using the number keys; with emacs, the Alt (meta) key and a number begins prefix entry. For example, to move the cursor forward by ten words, use ‘M-1 0 M-f’ in emacs mode, and ‘10w’ in vi.

Mode key bindings are defined in a set of named tables: vi-edit and emacs-edit for keys used when line editing at the command prompt; vi-choice and emacs-choice for keys used when choosing from lists (such as produced by the choose-window command); and vi-copy and emacs-copy used in copy mode. The tables may be viewed with the list-keys command and keys modified or removed with bind-key and unbind-key.

The paste buffer key pastes the first line from the top paste buffer on the stack.

The synopsis for the copy-mode command is:

[-u] [-t target-pane]
Enter copy mode. The -u option scrolls one page up.

Each window displayed by tmux may be split into one or more panes; each pane takes up a certain area of the display and is a separate terminal. A window may be split into panes using the split-window command. Windows may be split horizontally (with the -h flag) or vertically. Panes may be resized with the resize-pane command (bound to ‘C-up’, ‘C-down’ ‘C-left’ and ‘C-right’ by default), the current pane may be changed with the select-pane command and the rotate-window and swap-pane commands may be used to swap panes without changing their position. Panes are numbered beginning from zero in the order they are created.

A number of preset layouts are available. These may be selected with the select-layout command or cycled with next-layout (bound to ‘Space’ by default); once a layout is chosen, panes within it may be moved and resized as normal.

The following layouts are supported:

Panes are spread out evenly from left to right across the window.
Panes are spread evenly from top to bottom.
A large (main) pane is shown at the top of the window and the remaining panes are spread from left to right in the leftover space at the bottom. Use the main-pane-height window option to specify the height of the top pane.
Similar to main-horizontal but the large pane is placed on the left and the others spread from top to bottom along the right. See the main-pane-width window option.
Panes are spread out as evenly as possible over the window in both rows and columns.

In addition, select-layout may be used to apply a previously used layout - the list-windows command displays the layout of each window in a form suitable for use with select-layout. For example:

$ tmux list-windows
0: ksh [159x48]
    layout: bb62,159x48,0,0{79x48,0,0,79x48,80,0}
$ tmux select-layout bb62,159x48,0,0{79x48,0,0,79x48,80,0}

tmux automatically adjusts the size of the layout for the current window size. Note that a layout cannot be applied to a window with more panes than that from which the layout was originally defined.

Commands related to windows and panes are as follows:

[-d] [-t target-pane]
(alias: breakp)
Break target-pane off from its containing window to make it the only pane in a new window. If -d is given, the new window does not become the current window.
[-b buffer-index] [-t target-pane]
(alias: capturep)
Capture the contents of a pane to the specified buffer, or a new buffer if none is specified.
[-t target-window] [template]
Put a window into client choice mode, allowing a client to be selected interactively from a list. After a client is chosen, ‘%%’ is replaced by the client pty(4) path in template and the result executed as a command. If template is not given, "detach-client -t '%%'" is used. This command works only from inside tmux.
[-t target-window] [template]
Put a window into session choice mode, where a session may be selected interactively from a list. When one is chosen, ‘%%’ is replaced by the session name in template and the result executed as a command. If template is not given, "switch-client -t '%%'" is used. This command works only from inside tmux.
[-t target-window] [template]
Put a window into window choice mode, where a window may be chosen interactively from a list. After a window is selected, ‘%%’ is replaced by the session name and window index in template and the result executed as a command. If template is not given, "select-window -t '%%'" is used. This command works only from inside tmux.
[-t target-client]
(alias: displayp)
Display a visible indicator of each pane shown by target-client. See the display-panes-time, display-panes-colour, and display-panes-active-colour session options. While the indicator is on screen, a pane may be selected with the ‘0’ to ‘9’ keys.
[-t target-window] match-string
(alias: findw)
Search for the fnmatch(3) pattern match-string in window names, titles, and visible content (but not history). If only one window is matched, it'll be automatically selected, otherwise a choice list is shown. This command only works from inside tmux.
[-dhv] [-l size | -p percentage] [-s src-pane] [-t dst-pane]
(alias: joinp)
Like split-window, but instead of splitting dst-pane and creating a new pane, split it and move src-pane into the space. This can be used to reverse break-pane.
[-a] [-t target-pane]
(alias: killp)
Destroy the given pane. If no panes remain in the containing window, it is also destroyed. The -a option kills all but the pane given with -t.
[-t target-window]
(alias: killw)
Kill the current window or the window at target-window, removing it from any sessions to which it is linked.
[-t target-window]
(alias: lastp)
Select the last (previously selected) pane.
[-t target-session]
(alias: last)
Select the last (previously selected) window. If no target-session is specified, select the last window of the current session.
[-dk] [-s src-window] [-t dst-window]
(alias: linkw)
Link the window at src-window to the specified dst-window. If dst-window is specified and no such window exists, the src-window is linked there. If -k is given and dst-window exists, it is killed, otherwise an error is generated. If -d is given, the newly linked window is not selected.
[-t target-window]
(alias: lsp)
List the panes in the current window or in target-window.
[-t target-session]
(alias: lsw)
List windows in the current session or in target-session.
[-dk] [-s src-window] [-t dst-window]
(alias: movew)
This is similar to link-window, except the window at src-window is moved to dst-window.
[-adkP] [-n window-name] [-t target-window] [shell-command]
(alias: neww)
Create a new window. With -a, the new window is inserted at the next index up from the specified target-window, moving windows up if necessary, otherwise target-window is the new window location.

If -d is given, the session does not make the new window the current window. target-window represents the window to be created; if the target already exists an error is shown, unless the -k flag is used, in which case it is destroyed. shell-command is the command to execute. If shell-command is not specified, the value of the default-command option is used.

When the shell command completes, the window closes. See the remain-on-exit option to change this behaviour.

The TERM environment variable must be set to “screen” for all programs running inside tmux. New windows will automatically have “TERM=screen” added to their environment, but care must be taken not to reset this in shell start-up files.

The -P option prints the location of the new window after it has been created.

[-t target-window]
(alias: nextl)
Move a window to the next layout and rearrange the panes to fit.
[-a] [-t target-session]
(alias: next)
Move to the next window in the session. If -a is used, move to the next window with a bell, activity or content alert.
[-o] [-t target-pane] [shell-command]
(alias: pipep)
Pipe any output sent by the program in target-pane to a shell command. A pane may only be piped to one command at a time, any existing pipe is closed before shell-command is executed. The shell-command string may contain the special character sequences supported by the status-left command. If no shell-command is given, the current pipe (if any) is closed.

The -o option only opens a new pipe if no previous pipe exists, allowing a pipe to be toggled with a single key, for example:

bind-key C-p pipe-pane -o 'cat >>~/output.#I-#P'
[-t target-window]
(alias: prevl)
Move to the previous layout in the session.
[-a] [-t target-session]
(alias: prev)
Move to the previous window in the session. With -a, move to the previous window with a bell, activity or content alert.
[-t target-window] new-name
(alias: renamew)
Rename the current window, or the window at target-window if specified, to new-name.
[-DLRU] [-t target-pane] [adjustment]
(alias: resizep)
Resize a pane, upward with -U (the default), downward with -D, to the left with -L and to the right with -R. The adjustment is given in lines or cells (the default is 1).
[-k] [-t target-window] [shell-command]
(alias: respawnw)
Reactivate a window in which the command has exited (see the remain-on-exit window option). If shell-command is not given, the command used when the window was created is executed. The window must be already inactive, unless -k is given, in which case any existing command is killed.
[-DU] [-t target-window]
(alias: rotatew)
Rotate the positions of the panes within a window, either upward (numerically lower) with -U or downward (numerically higher).
[-t target-window] [layout-name]
(alias: selectl)
Choose a specific layout for a window. If layout-name is not given, the last preset layout used (if any) is reapplied.
[-DLRU] [-t target-pane]
(alias: selectp)
Make pane target-pane the active pane in window target-window. If one of -D, -L, -R, or -U is used, respectively the pane below, to the left, to the right, or above the target pane is used.
[-t target-window]
(alias: selectw)
Select the window at target-window.
[-dhvP] [-l size | -p percentage] [-t target-pane] [shell-command]
(alias: splitw)
Create a new pane by splitting target-pane: -h does a horizontal split and -v a vertical split; if neither is specified, -v is assumed. The -l and -p options specify the size of the new pane in lines (for vertical split) or in cells (for horizontal split), or as a percentage, respectively. All other options have the same meaning as for the new-window command.
[-dDU] [-s src-pane] [-t dst-pane]
(alias: swapp)
Swap two panes. If -U is used and no source pane is specified with -s, dst-pane is swapped with the previous pane (before it numerically); -D swaps with the next pane (after it numerically). -d instructs tmux not to change the active pane.
[-d] [-s src-window] [-t dst-window]
(alias: swapw)
This is similar to link-window, except the source and destination windows are swapped. It is an error if no window exists at src-window.
[-k] [-t target-window]
(alias: unlinkw)
Unlink target-window. Unless -k is given, a window may be unlinked only if it is linked to multiple sessions - windows may not be linked to no sessions; if -k is specified and the window is linked to only one session, it is unlinked and destroyed.

tmux allows a command to be bound to most keys, with or without a prefix key. When specifying keys, most represent themselves (for example ‘A’ to ‘Z’). Ctrl keys may be prefixed with ‘C-’ or ‘^’, and Alt (meta) with ‘M-’. In addition, the following special key names are accepted: Up, Down, Left, Right, BSpace, BTab, DC (Delete), End, Enter, Escape, F1 to F20, Home, IC (Insert), NPage (Page Up), PPage (Page Down), Space, and Tab. Note that to bind the ‘"’ or ‘'’ keys, quotation marks are necessary, for example: 
bind-key '"' split-window
bind-key "'" new-window

Commands related to key bindings are as follows:

[-cnr] [-t key-table] key command [arguments]
(alias: bind)
Bind key key to command. By default (without -t) the primary key bindings are modified (those normally activated with the prefix key); in this case, if -n is specified, it is not necessary to use the prefix key, command is bound to key alone. The -r flag indicates this key may repeat, see the repeat-time option.

If -t is present, key is bound in key-table: the binding for command mode with -c or for normal mode without. To view the default bindings and possible commands, see the list-keys command.

[-t key-table]
(alias: lsk)
List all key bindings. Without -t the primary key bindings - those executed when preceded by the prefix key - are printed. Keys bound without the prefix key (see bind-key -n) are marked with ‘(no prefix)’.

With -t, the key bindings in key-table are listed; this may be one of: vi-edit, emacs-edit, vi-choice, emacs-choice, vi-copy or emacs-copy.

[-t target-pane] key ...
(alias: send)
Send a key or keys to a window. Each argument key is the name of the key (such as ‘C-a’ or ‘npage’ ) to send; if the string is not recognised as a key, it is sent as a series of characters. All arguments are sent sequentially from first to last.
[-t target-pane]
Send the prefix key to a window as if it was pressed. If multiple prefix keys are configured, only the first is sent.
[-acn] [-t key-table] key
(alias: unbind)
Unbind the command bound to key. Without -t the primary key bindings are modified; in this case, if -n is specified, the command bound to key without a prefix (if any) is removed. If -a is present, all key bindings are removed.

If -t is present, key in key-table is unbound: the binding for command mode with -c or for normal mode without.

The appearance and behaviour of tmux may be modified by changing the value of various options. There are three types of option: server options, session options and window options.

The tmux server has a set of global options which do not apply to any particular window or session. These are altered with the set-option -s command, or displayed with the show-options -s command.

In addition, each individual session may have a set of session options, and there is a separate set of global session options. Sessions which do not have a particular option configured inherit the value from the global session options. Session options are set or unset with the set-option command and may be listed with the show-options command. The available server and session options are listed under the set-option command.

Similarly, a set of window options is attached to each window, and there is a set of global window options from which any unset options are inherited. Window options are altered with the set-window-option command and can be listed with the show-window-options command. All window options are documented with the set-window-option command.

Commands which set options are as follows:

[-agsuw] [-t target-session | target-window] option value
(alias: set)
Set a window option with -w (equivalent to the set-window-option command), a server option with -s, otherwise a session option.

If -g is specified, the global session or window option is set. With -a, and if the option expects a string, value is appended to the existing setting. The -u flag unsets an option, so a session inherits the option from the global options. It is not possible to unset a global option.

Available window options are listed under set-window-option.

Available server options are:

number
Set the number of buffers; as new buffers are added to the top of the stack, old ones are removed from the bottom if necessary to maintain this maximum length.
Set the time in milliseconds for which tmux waits after an escape is input to determine if it is part of a function or meta key sequences. The default is 500 milliseconds.
If enabled, the server will exit when there are no attached clients, rather than when there are no attached sessions.
Enable or disable the display of various informational messages (see also the -q command line flag).

Available session options are:

index
Set the base index from which an unused index should be searched when a new window is created. The default is zero.
[any | none | current]
Set action on window bell. any means a bell in any window linked to a session causes a bell in the current window of that session, none means all bells are ignored and current means only bell in windows other than the current window are ignored.
shell-command
Set the command used for new windows (if not specified when the window is created) to shell-command, which may be any sh(1) command. The default is an empty string, which instructs tmux to create a login shell using the value of the default-shell option.
path
Set the default working directory for processes created from keys, or interactively from the prompt. The default is empty, which means to use the working directory of the shell from which the server was started if it is available or the user's home if not.
path
Specify the default shell. This is used as the login shell for new windows when the default-command option is set to empty, and must be the full path of the executable. When started tmux tries to set a default value from the first suitable of the SHELL environment variable, the shell returned by getpwuid(3), or /bin/sh. This option should be configured when tmux is used as a login shell.
terminal
Set the default terminal for new windows created in this session - the default value of the TERM environment variable. For tmux to work correctly, this must be set to ‘screen’ or a derivative of it.
If enabled and the session is no longer attached to any clients, it is destroyed.
If on (the default), the client is detached when the session it is attached to is destroyed. If off, the client is switched to the most recently active of the remaining sessions.
colour
Set the colour used by the display-panes command to show the indicator for the active pane.
colour
Set the colour used by the display-panes command to show the indicators for inactive panes.
time
Set the time in milliseconds for which the indicators shown by the display-panes command appear.
time
Set the amount of time for which status line messages and other on-screen indicators are displayed. time is in milliseconds.
lines
Set the maximum number of lines held in window history. This setting applies only to new windows - existing window histories are not resized and retain the limit at the point they were created.
number
Lock the session (like the lock-session command) after number seconds of inactivity, or the entire server (all sessions) if the lock-server option is set. The default is not to lock (set to 0).
shell-command
Command to run when locking each client. The default is to run lock(1) with -np.
[on | off]
If this option is on (the default), instead of each session locking individually as each has been idle for lock-after-time, the entire server will lock after all sessions would have locked. This has no effect as a session option; it must be set as a global option.
attributes
Set status line message attributes, where attributes is either none or a comma-delimited list of one or more of: bright (or bold), dim, underscore, blink, reverse, hidden, or italics.
colour
Set status line message background colour, where colour is one of: black, red, green, yellow, blue, magenta, cyan, white, colour0 to colour255 from the 256-colour palette, or default.
colour
Set status line message foreground colour.
number
Set the number of error or information messages to save in the message log for each client. The default is 20.
[on | off]
If on, tmux captures the mouse and when a window is split into multiple panes the mouse may be used to select the current pane. The mouse click is also passed through to the application as normal.
colour
 
colour
Set the pane border colour for the currently active pane.
colour
 
colour
Set the pane border colour for panes aside from the active pane.
keys
Set the keys accepted as a prefix key. keys is a comma-separated list of key names, each of which individually behave as the prefix key.
time
Allow multiple commands to be entered without pressing the prefix-key again in the specified time milliseconds (the default is 500). Whether a key repeats may be set when it is bound using the -r flag to bind-key. Repeat is enabled for the default keys bound to the resize-pane command.
[on | off]
If enabled, request mouse input as UTF-8 on UTF-8 terminals.
[on | off]
Set the remain-on-exit window option for any windows first created in this session. When this option is true, windows in which the running program has exited do not close, instead remaining open but inactivate. Use the respawn-window command to reactivate such a window, or the kill-window command to destroy it.
[on | off]
Attempt to set the window title using the \e]2;...\007 xterm code if the terminal appears to be an xterm. This option is off by default. Note that elinks will only attempt to set the window title if the STY environment variable is set.
string
String used to set the window title if set-titles is on. Character sequences are replaced as for the status-left option.
[on | off]
Show or hide the status line.
attributes
Set status line attributes.
colour
Set status line background colour.
colour
Set status line foreground colour.
interval
Update the status bar every interval seconds. By default, updates will occur every 15 seconds. A setting of zero disables redrawing at interval.
[left | centre | right]
Set the position of the window list component of the status line: left, centre or right justified.
[vi | emacs]
Use vi or emacs-style key bindings in the status line, for example at the command prompt. The default is emacs, unless the VISUAL or EDITOR environment variables are set and contain the string ‘vi’.
string
Display string to the left of the status bar. string will be passed through strftime(3) before being used. By default, the session name is shown. string may contain any of the following special character sequences:
Character pair Replaced with
First line of the command's output
Colour or attribute change
Hostname of local host
Current window flag
Current window index
Current pane index
Session name
Current window title
Current window name
A literal ‘#’

The #(shell-command) form executes ‘shell-command’ and inserts the first line of its output. Note that shell commands are only executed once at the interval specified by the status-interval option: if the status line is redrawn in the meantime, the previous result is used. Shell commands are executed with the tmux global environment set (see the ENVIRONMENT section).

The window title (#T) is the title set by the program running within the window using the OSC title setting sequence, for example:

$ printf '\033]2;My Title\033\\'

When a window is first created, its title is the hostname.

#[attributes] allows a comma-separated list of attributes to be specified, these may be ‘fg=colour’ to set the foreground colour, ‘bg=colour’ to set the background colour, the name of one of the attributes (listed under the message-attr option) to turn an attribute on, or an attribute prefixed with ‘no’ to turn one off, for example nobright. Examples are:

#(sysctl vm.loadavg)
#[fg=yellow,bold]#(apm -l)%%#[default] [#S]

Where appropriate, special character sequences may be prefixed with a number to specify the maximum length, for example ‘#24T’.

By default, UTF-8 in string is not interpreted, to enable UTF-8, use the status-utf8 option.

attributes
Set the attribute of the left part of the status line.
colour
Set the background colour of the left part of the status line.
colour
Set the foreground colour of the left part of the status line.
length
Set the maximum length of the left component of the status bar. The default is 10.
string
Display string to the right of the status bar. By default, the current window title in double quotes, the date and the time are shown. As with status-left, string will be passed to strftime(3), character pairs are replaced, and UTF-8 is dependent on the status-utf8 option.
attributes
Set the attribute of the right part of the status line.
colour
Set the background colour of the right part of the status line.
colour
Set the foreground colour of the right part of the status line.
length
Set the maximum length of the right component of the status bar. The default is 40.
[on | off]
Instruct tmux to treat top-bit-set characters in the status-left and status-right strings as UTF-8; notably, this is important for wide characters. This option defaults to off.
string
Contains a list of entries which override terminal descriptions read using terminfo(5). string is a comma-separated list of items each a colon-separated string made up of a terminal type pattern (matched using fnmatch(3)) and a set of name=value entries.

For example, to set the ‘clear’ terminfo(5) entry to ‘\e[H\e[2J’ for all terminal types and the ‘dch1’ entry to ‘\e[P’ for the ‘rxvt’ terminal type, the option could be set to the string:

"*:clear=\e[H\e[2J,rxvt:dch1=\e[P"

The terminal entry value is passed through strunvis(3) before interpretation. The default value forcibly corrects the ‘colors’ entry for terminals which support 88 or 256 colours:

"*88col*:colors=88,*256col*:colors=256"
variables
Set a space-separated string containing a list of environment variables to be copied into the session environment when a new session is created or an existing session is attached. Any variables that do not exist in the source environment are set to be removed from the session environment (as if -r was given to the set-environment command). The default is "DISPLAY SSH_ASKPASS SSH_AUTH_SOCK SSH_AGENT_PID SSH_CONNECTION WINDOWID XAUTHORITY".
[on | off]
If on, display a status line message when activity occurs in a window for which the monitor-activity window option is enabled.
[on | off]
If this option is on, a message is shown on a bell instead of it being passed through to the terminal (which normally makes a sound). Also see the bell-action option.
[on | off]
Like visual-activity, display a message when content is present in a window for which the monitor-content window option is enabled.
[on | off]
If monitor-silence is enabled, prints a message after the interval has expired on a given window.
[-agu] [-t target-window] option value
(alias: setw)
Set a window option. The -a, -g and -u flags work similarly to the set-option command.

Supported window options are:

[on | off]
Aggressively resize the chosen window. This means that tmux will resize the window to the size of the smallest session for which it is the current window, rather than the smallest session to which it is attached. The window may resize when the current window is changed on another sessions; this option is good for full-screen programs which support SIGWINCH and poor for interactive programs such as shells.

[on | off]
This option configures whether programs running inside tmux may use the terminal alternate screen feature, which allows the smcup and rmcup terminfo(5) capabilities to be issued to preserve the existing window content on start and restore it on exit.

[on | off]
Control automatic window renaming. When this setting is enabled, tmux will attempt - on supported platforms - to rename the window to reflect the command currently running in it. This flag is automatically disabled for an individual window when a name is specified at creation with new-window or new-session, or later with rename-window. It may be switched off globally with: 
set-window-option -g automatic-rename off

colour
Set clock colour.

[12 | 24]
Set clock hour format.

height
 
width
Prevent tmux from resizing a window to greater than width or height. A value of zero restores the default unlimited setting.

height
 
width
Set the width or height of the main (left or top) pane in the main-horizontal or main-vertical layouts.

attributes
Set window modes attributes.

colour
Set window modes background colour.

colour
Set window modes foreground colour.

[vi | emacs]
Use vi or emacs-style key bindings in copy and choice modes. As with the status-keys option, the default is emacs, unless VISUAL or EDITOR contains ‘vi’.

[on | off]
Mouse state in modes. If on, the mouse may be used to copy a selection by dragging in copy mode, or to select an option in choice mode.

[on | off]
Monitor for activity in the window. Windows with activity are highlighted in the status line.

match-string
Monitor content in the window. When fnmatch(3) pattern match-string appears in the window, it is highlighted in the status line.

[interval]
Monitor for silence (no activity) in the window within interval seconds. Windows that have been silent for the interval are highlighted in the status line. An interval of zero disables the monitoring.

height
Set the height of the other panes (not the main pane) in the main-horizontal layout. If this option is set to 0 (the default), it will have no effect. If both the main-pane-height and other-pane-height options are set, the main pane will grow taller to make the other panes the specified height, but will never shrink to do so.

width
Like other-pane-height, but set the width of other panes in the main-vertical layout.

[on | off]
A window with this flag set is not destroyed when the program running in it exits. The window may be reactivated with the respawn-window command.

[on | off]
Duplicate input to any pane to all other panes in the same window (only for panes that are not in any special mode).

[on | off]
Instructs tmux to expect UTF-8 sequences to appear in this window.

attributes
Set status line attributes for a single window.

colour
Set status line background colour for a single window.

colour
Set status line foreground colour for a single window.

string
Set the format in which the window is displayed in the status line window list. See the status-left option for details of special character sequences available. The default is ‘#I:#W#F’.

attributes
Set status line attributes for windows which have an alert (bell, activity or content).

colour
Set status line background colour for windows with an alert.

colour
Set status line foreground colour for windows with an alert.

attributes
Set status line attributes for the currently active window.

colour
Set status line background colour for the currently active window.

colour
Set status line foreground colour for the currently active window.

string
Like window-status-format, but is the format used when the window is the current window.

string
Sets the window's conception of what characters are considered word separators, for the purposes of the next and previous word commands in copy mode. The default is ‘ -_@’.

[on | off]
If this option is set, tmux will generate xterm(1) -style function key sequences; these have a number included to indicate modifiers such as Shift, Alt or Ctrl. The default is off.
[-gsw] [-t target-session | target-window]
(alias: show)
Show the window options with -w (equivalent to show-window-options), the server options with -s, otherwise the session options for target session. Global session or window options are listed if -g is used.
[-g] [-t target-window]
(alias: showw)
List the window options for target-window, or the global window options if -g is used.

When the server is started, tmux copies the environment into the global environment; in addition, each session has a session environment. When a window is created, the session and global environments are merged. If a variable exists in both, the value from the session environment is used. The result is the initial environment passed to the new process.

The update-environment session option may be used to update the session environment from the client when a new session is created or an old reattached. tmux also initialises the TMUX variable with some internal information to allow commands to be executed from inside, and the TERM variable with the correct terminal setting of ‘screen’.

Commands to alter and view the environment are:

[-gru] [-t target-session] name [value]
(alias: setenv)
Set or unset an environment variable. If -g is used, the change is made in the global environment; otherwise, it is applied to the session environment for target-session. The -u flag unsets a variable. -r indicates the variable is to be removed from the environment before starting a new process.
[-g] [-t target-session]
(alias: showenv)
Display the environment for target-session or the global environment with -g. Variables removed from the environment are prefixed with ‘-’.

tmux includes an optional status line which is displayed in the bottom line of each terminal. By default, the status line is enabled (it may be disabled with the status session option) and contains, from left-to-right: the name of the current session in square brackets; the window list; the current window title in double quotes; and the time and date.

The status line is made of three parts: configurable left and right sections (which may contain dynamic content such as the time or output from a shell command, see the status-left, status-left-length, status-right, and status-right-length options below), and a central window list. By default, the window list shows the index, name and (if any) flag of the windows present in the current session in ascending numerical order. It may be customised with the window-status-format and window-status-current-format options. The flag is one of the following symbols appended to the window name:

Symbol Meaning
Denotes the current window.
Marks the last window (previously selected).
Window is monitored and activity has been detected.
! A bell has occurred in the window.
Window is monitored for content and it has appeared.
The window has been silent for the monitor-silence interval.

The # symbol relates to the monitor-activity and + to the monitor-content window options. The window name is printed in inverted colours if an alert (bell, activity or content) is present.

The colour and attributes of the status line may be configured, the entire status line using the status-attr, status-fg and status-bg session options and individual windows using the window-status-attr, window-status-fg and window-status-bg window options.

The status line is automatically refreshed at interval if it has changed, the interval may be controlled with the status-interval session option.

Commands related to the status line are as follows:

[-p prompts] [-t target-client] [template]
Open the command prompt in a client. This may be used from inside tmux to execute commands interactively. If template is specified, it is used as the command. If -p is given, prompts is a comma-separated list of prompts which are displayed in order; otherwise a single prompt is displayed, constructed from template if it is present, or ‘:’ if not. Before the command is executed, the first occurrence of the string ‘%%’ and all occurrences of ‘%1’ are replaced by the response to the first prompt, the second ‘%%’ and all ‘%2’ are replaced with the response to the second prompt, and so on for further prompts. Up to nine prompt responses may be replaced (‘%1’ to ‘%9’).
[-t target-client] command
(alias: confirm)
Ask for confirmation before executing command. This command works only from inside tmux.
[-p] [-t target-client] [message]
(alias: display)
Display a message. If -p is given, the output is printed to stdout, otherwise it is displayed in the target-client status line. The format of message is as for status-left, with the exception that #() are not handled.

tmux maintains a stack of paste buffers. Up to the value of the buffer-limit option are kept; when a new buffer is added, the buffer at the bottom of the stack is removed. Buffers may be added using copy-mode or the set-buffer command, and pasted into a window using the paste-buffer command.

A configurable history buffer is also maintained for each window. By default, up to 2000 lines are kept; this can be altered with the history-limit option (see the set-option command above).

The buffer commands are as follows:

[-t target-window] [template]
Put a window into buffer choice mode, where a buffer may be chosen interactively from a list. After a buffer is selected, ‘%%’ is replaced by the buffer index in template and the result executed as a command. If template is not given, "paste-buffer -b '%%'" is used. This command works only from inside tmux.
[-t target-pane]
(alias: clearhist)
Remove and free the history for the specified pane.
[-b buffer-index]
(alias: deleteb)
Delete the buffer at buffer-index, or the top buffer if not specified.
(alias: lsb)
List the global buffers.
[-b buffer-index] path
(alias: loadb)
Load the contents of the specified paste buffer from path.
[-dr] [-b buffer-index] [-s separator] [-t target-pane]
(alias: pasteb)
Insert the contents of a paste buffer into the specified pane. If not specified, paste into the current one. With -d, also delete the paste buffer from the stack. When output, any linefeed (LF) characters in the paste buffer are replaced with a separator, by default carriage return (CR). A custom separator may be specified using the -s flag. The -r flag means to do no replacement (equivalent to a separator of LF).
[-a] [-b buffer-index] path
(alias: saveb)
Save the contents of the specified paste buffer to path. The -a option appends to rather than overwriting the file.
[-b buffer-index] data
(alias: setb)
Set the contents of the specified buffer to data.
[-b buffer-index]
(alias: showb)
Display the contents of the specified buffer.

Miscellaneous commands are as follows:
[-t target-pane]
Display a large clock.
shell-command command
(alias: if)
Execute command if shell-command returns success.
(alias: lock)
Lock each client individually by running the command specified by the lock-command option.
shell-command
(alias: run)
Execute shell-command in the background without creating a window. After it finishes, any output to stdout is displayed in copy mode. If the command doesn't return success, the exit status is also displayed.
(alias: info)
Show server information and terminal details.

~/.tmux.conf
Default tmux configuration file.
/etc/tmux.conf
System-wide configuration file.

To create a new tmux session running vi(1):

$ tmux new-session vi

Most commands have a shorter form, known as an alias. For new-session, this is new:

$ tmux new vi

Alternatively, the shortest unambiguous form of a command is accepted. If there are several options, they are listed:

$ tmux n
ambiguous command: n, could be: new-session, new-window, next-window

Within an active session, a new window may be created by typing ‘C-b c’ (Ctrl followed by the ‘b’ key followed by the ‘c’ key).

Windows may be navigated with: ‘C-b 0’ (to select window 0), ‘C-b 1’ (to select window 1), and so on; ‘C-b n’ to select the next window; and ‘C-b p’ to select the previous window.

A session may be detached using ‘C-b d’ (or by an external event such as ssh(1) disconnection) and reattached with:

$ tmux attach-session

Typing ‘C-b ?’ lists the current key bindings in the current window; up and down may be used to navigate the list or ‘q’ to exit from it.

Commands to be run when the tmux server is started may be placed in the ~/.tmux.conf configuration file. Common examples include:

Changing the default prefix key:

set-option -g prefix C-a
unbind-key C-b
bind-key C-a send-prefix

Turning the status line off, or changing its colour:

set-option -g status off
set-option -g status-bg blue

Setting other options, such as the default command, or locking after 30 minutes of inactivity:

set-option -g default-command "exec /bin/ksh"
set-option -g lock-after-time 1800

Creating new key bindings:

bind-key b set-option status
bind-key / command-prompt "split-window 'exec man %%'"
bind-key S command-prompt "new-window -n %1 'ssh %1'"

pty(4)

Nicholas Marriott ⟨nicm@users.sourceforge.net⟩
November 25, 2024 BSD