This post provides a brief introduction to tmux and some commonly used commands and useful resources about tmux.
(Thanks Davide for recommending such a handy tool to me.)
(Stay tuned — I will update this post while I am gaining new skills about tmux.)
======What is tmux?
According to the tmux authors:
tmux is a terminal multiplexer. What is a terminal multiplexer? It lets you switch easily between several programs in one terminal, detach them (they keep running in the background) and reattach them to a different terminal. And do a lot more.
====== tmux sessions, windows, and panes explained
One of these features is the ability to break your session into more discreet components, called windows and panes. These are good for organizing multiple varied activities in a logical way.
Let’s look at how they relate to each other.
tmux sessions have windows, and windows have panes. Below you can see how how they are conceptualized:
- Sessions are for an overall theme, such as work, or experimentation, or sysadmin.
- Windows are for projects within that theme. So perhaps within your experimentation session you have a window titled noderestapi, and one titled lua sample.
- Panes are for views within your current project. So within your sysadmin session, which has a logs window, you may have a few panes for access logs, error logs, and system logs.
It’s also possible to create panes within a session without first creating a separate window. I do this sometimes. Hopefully it isn’t as horrible as it sounds right after reading about nesting.
Q about differences between sessions and windows and panes:
Can someone explain how they use sessions and windows and panes?
It feels like one too many levels, why both sessions AND windows?
I’m willing to believe there is a use case, but for the life of me I can’t come up with one.
I use sessions for different projects, and windows and panes within a project. For example, I’ll have a session for my puppet code, and a session for a bash script I’m working on. Within the puppet session, if I’m going to work on a new module, I open a new window. If I’m writing code in vim, I usually split off a pane so I can test running it next to it. Having the error output next to the code makes debugging really fast.
In a lot of ways, it basically acts like a tiling window manager for the terminal. The advantage over a window manager is that the whole layout can be accessed remotely. So if I’m working on a project from work, I can quickly resume working on the project from my home computer after SSH’ing in and reattaching to the tmux session.
====== see below for commonly used tmux comands
By default, tmux uses
Ctrl-b as its shortcut activation chord, which enables you perform a number of functions quickly.
- Switch between different windows
Ctrl – b (presee the ctrl and b keys at the same time and release them at the same time, and then immediately press window number) window number
- Cursor move within an active window
Ctrl-b (release the keys, and immediately press the “[” key ) the key with “[“.
when you see the cursor becomes a solid flashing diamond, you can use arrow key to move your cursor in the active terminal window.
Note: Press “q” to exit the cursor move mode.
- Session management
$rename the current session # default session name and window name is number, can rename session names to meaningful ones
ddetach from the current session
tmux is developed on a client-server model which means that the session is stored on the server and persist beyond ssh logout.
The following command will create a new session called mysession:
tmux new-session -s mysession
To attach to a session run:
tmux attach -t mysession
To list all session run:
You can kill a session using the following command:
tmux kill-session -t mysession
you can grossly kill all tmux processes with the following command:
pkill -f tmux
Frequently used sessions commands
Ctrl-b d Detach from the current session Ctrl-b ( Go to previous session Ctrl-b ) Go to next session Ctrl-b L Go to previously used session Ctrl-b s Choose a session from the sessions list
Ctrl + D — exit tmux from terminal.
- Windows (tabs) Management
Each session can have multiple windows. By default all windows are numbered starting from zero.
Frequently used windows (tabs) commands
Ctrl-b 1 Switch to window 1 Ctrl-b c Create new window Ctrl-b w List all windows Ctrl-b n Go to next window Ctrl-b p Go to previous window Ctrl-b f Find window Ctrl-b , Name window Ctrl-b w Choose a window from the windows list Ctrl-b & Kill the current window
- One of the handy things about tmux is how easy it is to resize panes:
Ctrl +b, followed by holding down Alt, and using the arrow keys to resize.
======things about how to save sessions and recover sessions.
- tmux died and says “no sessions” – is there any way to recover? (pdf)
- Restore tmux session after reboot (pdf)
If you reboot you computer you will lose the sessions. Sessions cannot be saved. But, they can be scripted. What most do in fact is to script some sessions so that you can re-create them.
- Installation with sudo privilege
Installation is pretty straightforward if you have Ubuntu or any other Debian-based distribution you can install tmux with:
sudo apt-get install tmux
yum install tmux
and on MacOS:
brew install tmux
Note: check the comments for some up-to-date scripts.
References and further reading list
- Getting started with tmux (March 30, 2017) — pdf
This tutorial covers installation of tmux and some commonly used commands.
This is a pretty good introduction to tmux, it includes why tmux and the comaprision between tmux and screen, as well as some tmux shortcuts
- tmux cheatsheet — pdf
- Another tmux cheatsheet — pdf
- Please read https://raw.githubusercontent.com/tmux/tmux/master/FAQ and tmux man page for more information on this.
- A Quick and Easy Guide to tmux (Aug 16, 2015)
- Tmux: A Simple Start (August 05, 2013)