āˆŸ"tmux" - Terminal Multiplexer

Provides a tutorial example on how to use 'tmux' tool to manage multiple shells as windows and panes in a single terminal. 'tmux' automatically keeps all shells running when the terminal is disconnected.

What Is "tmux"? - "tmux" 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.

Here is the official description of "tmux" from its manual page:

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
ā€˜C-b dā€™ 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.

"tmux" is a nice tool that reduces the number of remote "ssh" sessions, saves time on trying to push processes to the background manually to prevent be killed by connection timeouts. Here is what I tried on my CentOS computer.

1. Install "tmux":

herong$ sudo dnf install tmux

Installed:
 tmux-2.7-1.el8.x86_64

2. Use "tmux" command to start a new "tmux" session, which starts a shell as the first pane in the first window of the "tmux" session.

herong$ tmux
(in a child shell in "tmux")

herong$ exit
(back to the original shell)

3. Use the following hot keys to control its windows and tabs:

ctrl-b, %     split the screen in half from left to right
ctrl-b, "     split the screen in half from top to bottom
ctrl-b, array_key  switch to the pane in different directions
ctrl-b, c    create a new window
ctrl-b, 0|1|... switch to a given window
ctrl-b, d     detach from tmux, leaving it running in the background
...
ctrl-b, ?     display all hot keys

4. Use "tmux ls|attach" to list and reattach to a detached or disconnected tmux session.

herong$ tmux ls
0: 1 windows (created Tue Aug 25 20:16:44 2020) [122x42]

herong$ tmux attach
(old tmux is displayed again)

Table of Contents

 About This Book

 Introduction to Linux Systems

 Cockpit - Web Portal for Administrator

Process Management

 "ps" - Display Current Processes

 "jobs" - Manage Background Jobs

"tmux" - Terminal Multiplexer

 Files and Directories

 Users and Groups

 File Systems

 Block Devices and Partitions

 LVM (Logical Volume Manager)

 Installing CentOS

 SELinux - Security-Enhanced Linux

 Network Connection on CentOS

 Software Package Manager on CentOS - DNF and YUM

 Running Apache Web Server (httpd) on Linux Systems

 Running PHP Scripts on Linux Systems

 Running MySQL Database Server on Linux Systems

 Running Python Scripts on Linux Systems

 vsftpd - Very Secure FTP Daemon

 Postfix - Mail Transport Agent (MTA)

 Dovecot - IMAP and POP3 Server

 Email Client Tools - Mail User Agents (MUA)

 LDAP (Lightweight Directory Access Protocol)

 GCC - C/C++ Compiler

 Graphics Environments on Linux

 Conda - Environment and Package Manager

 Tools and Utilities

 Administrative Tasks

 References

 Full Version in PDF/EPUB