tio - a simple serial device I/O tool

1. Introduction

tio is a simple serial device tool which features a straightforward
command-line and configuration file interface to easily connect to serial TTY
devices for basic I/O operations.

1.1 Motivation

To make a simpler serial device tool for talking with serial TTY devices with
less focus on classic terminal/modem features and more focus on the needs of
embedded developers and hackers.

tio was originally created to replace
screen for connecting to serial devices
when used in combination with tmux.

2. Features

• Easily connect to serial TTY devices
• Automatic connect
• Support for arbitrary baud rates
• List available serial devices
• Show RX/TX statistics
• Toggle serial lines
• Pulse the DTR line
• Local echo support
• Remap special characters (nl, cr-nl, bs, etc.)
• Line timestamps
• Support for delayed output
• Hexadecimal mode
• Log to file
• Autogeneration of log filename
• Configuration file support
• Activate sub-configurations by name or pattern
• Redirect I/O to file or network socket for scripting or TTY sharing
• Pipe input and/or output
• Bash completion
• Color support
• Man page documentation

3. Usage

3.1 Command-line

The command-line interface is straightforward as reflected in the output from
'tio --help':

    Usage: tio [<options>] <tty-device|sub-config>
    Connect to tty device directly or via sub-configuration.
    Options:
      -b, --baudrate <bps>             Baud rate (default: 115200)
      -d, --databits 5|6|7|8           Data bits (default: 8)
      -f, --flow hard|soft|none        Flow control (default: none)
      -s, --stopbits 1|2               Stop bits (default: 1)
      -p, --parity odd|even|none       Parity (default: none)
      -o, --output-delay <ms>          Character output delay (default: 0)
          --dtr-pulse-duration <ms>    DTR pulse duration (default: 100)
      -n, --no-autoconnect             Disable automatic connect
      -e, --local-echo                 Enable local echo
      -t, --timestamp                  Enable line timestamp
          --timestamp-format <format>  Set timestamp format (default: 24hour)
      -L, --list-devices               List available serial devices
      -l, --log                        Enable log to file
          --log-file <filename>        Set log filename
          --log-strip                  Strip control characters and escape sequences
      -m, --map <flags>                Map special characters
      -c, --color 0..255|none|list     Colorize tio text (default: 15)
      -S, --socket <socket>            Redirect I/O to file or network socket
      -x, --hexadecimal                Enable hexadecimal mode
      -v, --version                    Display version
      -h, --help                       Display help
    Options and sub-configurations may be set via configuration file.
    In session, press ctrl-t q to quit.
    See the man page for more details.

By default tio automatically connects to the provided TTY device if present.
If the device is not present, it will wait for it to appear and then connect.
If the connection is lost (eg. device is unplugged), it will wait for the
device to reappear and then reconnect. However, if the --no-autoconnect
option is provided, tio will exit if the device is not present or an
established connection is lost.

tio features full bash autocompletion.

Typical use is without options:

$ tio /dev/ttyUSB0

Which corresponds to the commonly used default options:

$ tio -b 115200 -d 8 -f none -s 1 -p none /dev/ttyUSB0

It is recommended to connect serial tty devices by ID:

$ tio /dev/serial/by-id/usb-FTDI_TTL232R-3V3_FTGQVXBL-if00-port0

Using serial devices by ID ensures that tio automatically reconnects to the
correct serial device if it is disconnected and then reconnected.

3.2 Key commands

Various in session key commands are supported. When tio is started, press
ctrl-t ? to list the available key commands.

[20:19:12.040] Key commands:
[20:19:12.040]  ctrl-t ?   List available key commands
[20:19:12.040]  ctrl-t b   Send break
[20:19:12.040]  ctrl-t c   Show configuration
[20:19:12.040]  ctrl-t d   Toggle DTR line
[20:19:12.040]  ctrl-t D   Pulse DTR line
[20:19:12.040]  ctrl-t e   Toggle local echo mode
[20:19:12.040]  ctrl-t h   Toggle hexadecimal mode
[20:19:12.040]  ctrl-t l   Clear screen
[20:19:12.040]  ctrl-t L   Show line states
[20:19:12.040]  ctrl-t q   Quit
[20:19:12.040]  ctrl-t r   Toggle RTS line
[20:19:12.041]  ctrl-t s   Show statistics
[20:19:12.041]  ctrl-t t   Send ctrl-t key code
[20:19:12.041]  ctrl-t T   Toggle line timestamp mode
[20:19:12.041]  ctrl-t v   Show version

3.3 Configuration file

Options can be set via the configuration file first found in any of the
following locations in the order listed:

• $XDG_CONFIG_HOME/tio/tiorc
• $HOME/.config/tio/tiorc
• $HOME/.tiorc

The configuration file supports sub-configurations using named sections which can
be activated via the command-line by name or pattern. A sub-configuration
specifies which tty to connect to and other options.

Example configuration file:

# Defaults
baudrate = 9600
databits = 8
parity = none
stopbits = 1
color = 10
dtr-pulse-duration = 50
[rpi3]
tty = /dev/serial/by-id/usb-FTDI_TTL232R-3V3_FTGQVXBL-if00-port0
baudrate = 115200
no-autoconnect = enable
log = enable
log-file = rpi3.log
color = 12
[usb devices]
pattern = usb([0-9]*)
tty = /dev/ttyUSB%s
color = 13

To use a specific sub-configuration by name simply start tio like so:

$ tio rpi3

Or by pattern match:

$ tio usb12

4. Installation

4.1 Installation using package manager

Packages for various GNU/Linux distributions are available. Please consult your
package manager tool to find and install tio.

If you would like to see tio included in your favorite distribution, please
reach out to their package maintainers team.

4.2 Installation using snap

Install latest stable version:

    $ snap install tio

Install bleeding edge:

    $ snap install tio --edge

4.3 Installation from source

The latest source releases can be found here.

Install steps:

    $ meson build
    $ meson compile -C build
    $ meson install -C build

See meson_options.txt for tio specific build options.

Note: Please do no try to install from source if you are not familiar with
how to build stuff using meson.

5. Contributing

tio is open source. If you want to help out with the project please feel free
to join in.

All contributions (bug reports, code, doc, ideas, etc.) are welcome.

Please use the github issue tracker and pull request features.

Also, if you find this free open source software useful please feel free to
consider making a donation of your choice:

6. Support

Submit bug reports via GitHub: https://github.com/tio/tio/issues

7. Website

Visit tio.github.io

8. License

tio is GPLv2+. See LICENSE file for more details.

9. Authors

Created by Martin Lund <martin.lund@keep-it-simple.com>

See the AUTHORS file for full list of contributors.