Linux multi window terminal Screen and Tmux

Screen allows for multi window connection using a single ssh session. It also allows to detach from the session screen while still running a remote session.

Tmux

Sessions, windows(aka tabs) and panes

Tmux is a so-called terminal multiplexer. Simply speaking, tmux acts as a window manager within your terminal1 and allows you to create multiple windows and panes within a single terminal window. Within one terminal window you can open multiple windows and split-views (called “panes” in tmux lingo). Each pane will contain its own, independently running terminal instance. This allows you to have multiple terminal commands and applications running visually next to each other without the need to open multiple terminal emulator windows.

The server holds sessions and the windows and panes within them:

• session - is a set of windows, plus a notion of which window is current,there may be multiple sessions on a server,
• window(tab) - is a single screen covered with panes, each session may have many separate windows that you can switch between
• pane - is a rectangular part of a window that runs a specific command, e.g. a shell

Indicator, bottom left conrner

[0] 0:bash- 1:bash* 
# currently looking at 'tab 1' of tmux window(tab) '0'.

Install Tmux

Install - Linux via package manager

• sudo apt-get install tmux

Install - Windows

• Install Git for Windows SDK
• run /bin/pacman -S tmux

Quick Start

/usr/bin/tmux

Auto completion [1]

wget -q https://github.com/imomaliev/tmux-bash-completion/raw/master/completions/tmux -O ~/.bash_completion_tmux
# add to ~/.bashrc
echo "source ~/.bash_completion_tmux" >> ~/.bashrc

References

• [1] - https://github.com/imomaliev/tmux-bash-completion

Managging sessions

tmux new -s database #start new session named 'database'
tmux ls              #lists all detached sessions
tmux attach -t 0     #attach to terminal 0 session
tmux rename-session -t 0 database
tmux switch         -t <session_name>
tmux kill-session   -t <session_name>

Key bindings

• C^b :new<CR> new session
• C^b $ name session
• C^b ( previous session
• C^b ) next session
• C^b L 'last' (previously used) session
• C^b s choose a session from a list

Key bindings

Windows(aka tabs)

• C^b c create new window(aka tab), creates a full size window on top of your panes
• C^n c switch to next window(aka tab)
• C^p c switch to previous window(aka tab)
• C^l c switch to last window(aka tab)
• C^b , rename current window
• C^b d detach current session
• C^b D gives you a choice what session you wish to detach

Pane

• C^b " split a pane horizontally
• C^b % split a pane vertically
• C^b z full screen pane resize, repeat to get back
• C^d close a pane, also type 'exit'
• C^b Up,Down,Left,Right arrow move to neighbouring pane
• C^b q #index display pane numbers, then press 0..9 to move to #paneIndex
• C^b 0-9 move to the window based on index
• C^b [] {} swap panes [] left-right, {} up-down swap

Screen navigation, scroll and search

Function                     vi              emacs
--------                     --              -----
Half page down               C-d             M-Down
Half page up                 C-u             M-Up
Next page                    C-f             Page down
Previous page                C-b             Page up
Scroll down                  C-Down or C-e   C-Down
Scroll up                    C-Up or C-y     C-Up
Search again                 n               n
Search again in reverse      N               N
Search backward              ?               C-r
Search forward               /               C-s

Copy-paste default mode (Emacs style)

Ctrl+b,[         # enter 'copy mode'
                 # navigate using arrows to text you want to start coping
Ctrl+Space       # start coping (highlighting)
                 # move around using arrow keys to select region
Ctrl+w or Alt+w  # copy the region into the buffer
Ctrl+b,]         # paste in a possibly different Tmux pane/window
C^b,:show-buffer # show current buffer

Commands

C^b, :setw synchronize-panes on
C^b, :setw synchronize-panes off

Tmux Plugin Manager

Clone TPM

$ git clone https://github.com/tmux-plugins/tpm ~/.tmux/plugins/tpm

Put this at the bottom of ~/.tmux.conf ($XDG_CONFIG_HOME/tmux/tmux.conf works too):

# List of plugins
set -g @plugin 'tmux-plugins/tpm'
set -g @plugin 'tmux-plugins/tmux-resurrect'
# set -g @plugin 'tmux-plugins/tmux-sensible'

# Other examples:
# set -g @plugin 'github_username/plugin_name'
# set -g @plugin 'git@github.com/user/plugin'
# set -g @plugin 'git@bitbucket.com/user/plugin'

# Initialize TMUX plugin manager (keep this line at the very bottom of tmux.conf)
run -b '~/.tmux/plugins/tpm/tpm'

Reload TMUX environment so TPM is sourced:

# type this in Tmux terminal if tmux is already running
$ tmux source ~/.tmux.conf

That's it!

Installing plugins

1. Add new plugin to ~/.tmux.conf with set -g @plugin '...'
2. Press prefix + I (capital i, as in Install) to fetch the plugin.

You're good to go! The plugin was cloned to ~/.tmux/plugins/ dir and sourced.

Uninstalling plugins

1. Remove (or comment out) plugin from the list.
2. Press prefix + alt + u (lowercase u as in uninstall) to remove the plugin.

All the plugins are installed to ~/.tmux/plugins/ so alternatively you can find plugin directory there and remove it.

Tmux Resurrect

Restore tmux environment after system restart.

Installation with Tmux Plugin Manager (recommended)

Add plugin to the list of TPM plugins in .tmux.conf:

set -g @plugin 'tmux-plugins/tmux-resurrect'

Hit prefix + I to fetch the plugin and source it. You should now be able to use the plugin, no restart required.

Key bindings

• prefix + Ctrl-s - save
• prefix + Ctrl-r - restore

Tmuxinator

Create and manage tmux sessions easily.

Screen

sudo apt-get install screen

Key terms

• window - it's a separate window that you can switch between
• region - your terminal screen can be divided in regions where each can hold multiple windows

Useful commands and key bindings

$ screen -ls   #list detached sessions
$ screen -r    #re attach

Quick start

• C^a c create new prompt
• C^a tab move to a next window
• C^a | split vertically
• C^a S split horizontly
• C^a \ kill all windows, terminate any ssh sessions and exit GNU Screen program

Key bindings

Key	Action	Notes
Ctrl+a c	new window
Ctrl+a n	next window	I bind F12 to this
Ctrl+a p	previous window	I bind F11 to this
Ctrl+a "	select window from list	I have window list in the status line
Ctrl+a	previous window viewed
Ctrl+a S	split terminal horizontally into regions	Ctrl+a c to create new window there
Ctrl+a |	split terminal vertically into regions	Requires screen >= 4.1
Ctrl+a :resize	resize region
Ctrl+a :fit	fit screen size to new terminal size	Ctrl+a F is the same. Do after resizing xterm
Ctrl+a :remove	remove region	Ctrl+a X is the same
Ctrl+a tab	Move to next region
Ctrl+a d	detach screen from terminal	Start screen with -r option to reattach
Ctrl+a A	set window title
Ctrl+a x	lock session	Enter user password to unlock
Ctrl+a [	enter scrollback/copy mode	Enter to start and end copy region. Ctrl+a ] to leave this mode
Ctrl+a ]	paste buffer	Supports pasting between windows
Ctrl+a >	write paste buffer to file	useful for copying between screens
Ctrl+a <	read paste buffer from file	useful for pasting between screens
Ctrl+a ?	show key bindings/command names	Note unbound commands only in man page
Ctrl+a :	goto screen command prompt	up shows last command entered

Scroll back - a copy mode

In GNU Screen press Ctrl + a + [ or C^a C^ESC to enter Copy Mode, then scroll PgUp/PgDown or up/down using keys j or k. Use Enter key to start and end selection coping to registry/buffer. Below are some other navigation keys:

h -    Move the cursor left by one character
j -    Move the cursor down by one line
k -    Move the cursor up by one line
l -    Move the cursor right by one character
0 -    Move to the beginning of the current line
$ -    Move to the end of the current line.
G -    Moves to the specified line
       (defaults to the end of the buffer).
C-u -  Scrolls a half page up.
C-b -  Scrolls a full page up.
C-d -  Scrolls a half page down.
C-f -  Scrolls the full page down.
PgUp / PgDown - Scrolls a page up/down

Define scrollback buffer size start screen with the following key (5000 lines in this example):

screen -h 5000

Update: You can use activate copy mode of GNU Screen also by Ctrl + Esc that might be more useful than Ctrl + a + [ shortcut (thanks to Yu-Jie Lin for this tip).

Custom configuration

By default the config is kept in ~/.screenrc file but using -c option we can pass a custom config

~$ screen -c screen-4regions.screen

Example of a config file:

~$ cat screen-4regions.screen
layout FourScreens    #it's a new feature, makes screen aware of regions layout
# Region 0
screen -t mail1-queue     #creates new terminal/prompt
select 0                  #select window0
stuff "echo Window0^M"    #echo a string between quotes, ^M translates to EOL means enter-return key
stuff "sshpass -p 'password' ssh -o PubkeyAuthentication=no root@example.com^M"  #ssh interactively
 
split      #split horizontally
split -v   #split vertically

# Region 1 
select 1
focus #get focus on a selected region
screen -t mail2-queue sshpass -p 'password' ssh -o PubkeyAuthentication=no root@example.com
                      #create a new terminal/prompt '''-t mail2-queue''' in the focus window and
                      #executes the command
stuff "echo Window1^M"

# Region 2
select 2
focus
screen -t mail1
stuff "echo Window2^M"

split -v

# Region 3
select 3
focus
screen -t mail2
stuff "echo Window3^M"

altscreen on                                                                                       
term screen-256color                                                                               
bind ',' prev                                                                                      
bind '.' next                                                                                      
#                                                                                                  
#change the hardstatus settings to give an window list at the bottom of the                        
#screen, with the time and date and with the current window highlighted                            
hardstatus alwayslastline                                                                          
#hardstatus string '%{= kG}%-Lw%{= kW}%50> %n%f* %t%{= kG}%+Lw%< %{= kG}%-=%c:%s%{-}'              
hardstatus string '%{= kG}[ %{G}%H %{g}][%= %{= kw}%?%-Lw%?%{r}(%{W}%n*%f%t%?(%u)%?%{r})%{w}%?%+Lw%?%?%= %{g}][%{B} %m-%d %{W}%c %{g}]'
#layout save default   #makes regions saved when you re-attach a session

Terminator

Terminator is user frendly, gui scalable terminal with layouts, multi windows, tabs and broadcast function

$ sudo apt install terminator

Useful key bindings

Alt+Arrow      Move to another terminal
C^+Shift+X     Maximise current window, press again to revert
C^+Shift+Z     Zooms the current terminal, press again to revert
C^+Shift+O     Split terminals Horizontally.
C^+Shift+E     Split terminals Vertically.
C^+Shift+Arrow Resize windows by moving parent dragbar
C^+Shift+T     Open new tab
C^+Shift+PgUp  Switch between tabs, PgDown in reverse order
C^+Shift+W     Close the current terminal.
C^+Shift+Q     Quit terminator
C^+Plus (+)    Increase  font  size. Note: this may require you to press shift, depending on your keyboard
C^+Minus(-)    Decrease font size. Note: this may require you to  press  shift
C^+Zero        Restore font size to original setting.
Super+G        Group all
Super+Shift+G  Ungroup all

Issues:

• broadcast group inserting chars twice

References

• User Guide HTML one page
• Tmux Official website
• tmux cheat sheet TOP CLASS!
• Terminator Key bindings man page