
[![tio](images/tio-icon.png)]()

# tio - a serial device I/O tool

[![](https://img.shields.io/github/actions/workflow/status/tio/tio/ubuntu.yml?label=Ubuntu)](https://github.com/tio/tio/actions/workflows/ubuntu.yml)
[![](https://img.shields.io/github/actions/workflow/status/tio/tio/macos.yml?label=MacOS)](https://github.com/tio/tio/actions/workflows/macos.yml)
[![](https://github.com/tio/tio/actions/workflows/codeql.yml/badge.svg)](https://github.com/tio/tio/actions/workflows/codeql.yml)
[![](https://img.shields.io/codefactor/grade/github/tio/tio)](https://www.codefactor.io/repository/github/tio/tio)
[![](https://img.shields.io/github/v/release/tio/tio?sort=semver)](https://github.com/tio/tio/releases)
[![](https://img.shields.io/repology/repositories/tio)](https://repology.org/project/tio/versions)

## 1. Introduction

tio is a 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.

<p align="center">
<img src="images/tio-demo.gif">
</p>

### 1.1 Motivation

To make a simpler serial device tool for working 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 as an alternative to
[screen](https://www.gnu.org/software/screen) for connecting to serial devices
when used in combination with [tmux](https://tmux.github.io).

## 2. Features

 * Easily connect to serial TTY devices
 * Sensible defaults (115200 8n1)
 * Automatic connection management
   * Automatic detection of serial ports
   * Automatic reconnect
   * Automatically connect to first new appearing serial device
   * Automatically connect to latest registered serial device
 * Connect to same port/device combination via unique topology ID (TID)
   * Useful for reconnecting when serial device has no serial device by ID
 * Support for non-standard baud rates
 * Support for mark and space parity
 * X-modem (1K/CRC) and Y-modem file upload
 * Support for RS-485 mode
 * List available serial devices
   * By device
     * Including topology ID, uptime, driver, description
     * Sorted by uptime (newest device listed last)
   * By ID
   * By path
 * Show RX/TX statistics
 * Toggle serial lines
 * Pulse serial lines with configurable pulse duration
 * Local echo support
 * Remapping of characters (nl, cr-nl, bs, lowercase to uppercase, etc.)
 * Switchable independent input and output
   * Normal mode
   * Hex mode (output supports variable width)
   * Line mode (input only)
 * Timestamp support
   * Per line in normal output mode
   * Output timeout timestamps in hex output mode
 * Support for delayed output
   * Per character
   * Per line
 * Log to file
   * Automatic naming of log file (default)
   * Configurable directory for saving automatic named log files
   * Manual naming of log file
   * Overwrite (default) or append to log file
   * Strip control characters and escape sequences
 * Configuration file support
   * Support for configuration profiles
   * Activate configuration profiles by name or pattern
   * Support for including other configuration files
 * Redirect I/O of shell command to serial device
 * Redirect I/O to UNIX socket or IPv4/v6 network socket
   * Useful for scripting or TTY sharing
 * Pipe input and/or output
 * Bash completion on options, serial device names, and profile names
 * Configurable tio message text color
   * Supports NO_COLOR env variable as per [no-color.org](https://no-color.org)
 * Visual or audible alert on connect/disconnect
 * Remapping of prefix key
 * Lua scripting support for automation
   * Run script manually or automatically at connect (once/always/never)
   * Simple expect/send like functionality with support for regular expressions
   * Manipulate port modem lines (useful for microcontroller reset/boot etc.)
   * Send files via x/y-modem protocol
   * Search for serial devices
 * Man page documentation
 * Plays nicely with [tmux](https://tmux.github.io) and similar terminal multiplexers

## 3. Usage

For more usage details please see the man page documentation
[here](https://raw.githubusercontent.com/tio/tio/master/man/tio.1.txt).

### 3.1 Command-line

The command-line interface is straightforward as reflected in the output from
```tio --help```:
```
Usage: tio [<options>] <tty-device|profile|tid>

Connect to TTY device directly or via configuration profile or topology ID.

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|mark|space  Parity (default: none)
  -o, --output-delay <ms>                Output character delay (default: 0)
  -O, --output-line-delay <ms>           Output line delay (default: 0)
      --line-pulse-duration <duration>   Set line pulse duration
  -a, --auto-connect new|latest|direct   Automatic connect strategy (default: direct)
      --exclude-devices <pattern>        Exclude devices by pattern
      --exclude-drivers <pattern>        Exclude drivers by pattern
      --exclude-tids <pattern>           Exclude topology IDs by pattern
  -n, --no-reconnect                     Do not reconnect
  -e, --local-echo                       Enable local echo
      --input-mode normal|hex|line       Select input mode (default: normal)
      --output-mode normal|hex|hexN      Select output mode (default: normal)
  -t, --timestamp                        Enable line timestamp
      --timestamp-format <format>        Set timestamp format (default: 24hour)
      --timestamp-timeout <ms>           Set timestamp timeout (default: 200)
  -l, --list                             List available serial devices, TIDs, and profiles
  -L, --log                              Enable log to file
      --log-file <filename>              Set log filename
      --log-directory <path>             Set log directory path for automatic named logs
      --log-append                       Append to log file
      --log-strip                        Strip control characters and escape sequences
  -m, --map <flags>                      Map characters
  -c, --color 0..255|bold|none|list      Colorize tio text (default: bold)
  -S, --socket <socket>                  Redirect I/O to socket
      --rs-485                           Enable RS-485 mode
      --rs-485-config <config>           Set RS-485 configuration
      --alert bell|blink|none            Alert on connect/disconnect (default: none)
      --mute                             Mute tio messages
      --script <string>                  Run script from string
      --script-file <filename>           Run script from file
      --script-run once|always|never     Run script on connect (default: always)
      --exec <command>                   Execute shell command with I/O redirected to device
  -v, --version                          Display version
  -h, --help                             Display help

Options and profiles may be set via configuration file.

In session you can press ctrl-t ? to list available key commands.

See the man page for more details.
```

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

#### 3.1.1 Examples

Typical use is without options:
```
$ tio /dev/ttyUSB0
```

Which corresponds to the commonly used default options:
```
$ tio --baudrate 115200 --databits 8 --flow none --stopbits 1 --parity none /dev/ttyUSB0
```

List available serial devices:
```
$ tio --list
Device            TID     Uptime [s] Driver           Description
----------------- ---- ------------- ---------------- --------------------------
/dev/ttyS4        BaaB     19526.576 port             16550A UART
/dev/ttyS5        eV0Z     19525.845 port             16550A UART
/dev/ttyUSB1      bCC2      1023.274 ftdi_sio         TTL232R-3V3
/dev/ttyUSB0      SPpw       978.527 ftdi_sio         TTL232RG-VREG3V3
/dev/ttyACM0      i5q4         2.079 cdc_acm          ST-Link VCP Ctrl

By-id
--------------------------------------------------------------------------------
/dev/serial/by-id/usb-FTDI_TTL232R-3V3_FTCHUV56-if00-port0
/dev/serial/by-id/usb-FTDI_TTL232RG-VREG3V3_FT1NELUB-if00-port0
/dev/serial/by-id/usb-STMicroelectronics_STLINK-V3_004900343438510234313939-if02

By-path
--------------------------------------------------------------------------------
/dev/serial/by-path/pci-0000:00:14.0-usb-0:8.1.3.1.4:1.0-port0
/dev/serial/by-path/pci-0000:00:14.0-usbv2-0:8.1.3.1.4:1.0-port0
/dev/serial/by-path/pci-0000:00:14.0-usbv2-0:6.4:1.0-port0
/dev/serial/by-path/pci-0000:00:14.0-usb-0:6.4:1.0-port0
/dev/serial/by-path/pci-0000:00:14.0-usbv2-0:6.3:1.2
/dev/serial/by-path/pci-0000:00:14.0-usb-0:6.3:1.2

Configuration profiles (/home/lundmar/.config/tio/config)
--------------------------------------------------------------------------------
rpi3                stm32               esp32               am64-evm
imx8mp-evk          nucleo-h743zi2      usb-devices
```

It is recommended to connect serial TTY devices by ID:
```
$ tio /dev/serial/by-id/usb-FTDI_TTL232R-3V3_FTCHUV56-if00-port0
```
Note: Using serial devices by ID helps ensure that tio automatically reconnects
to the same serial device when reattached, even when it enumerates differently.

If no serial device by ID is available it is recommended to connect via
topology ID (TID):
```
$ tio bCC2
```
Note: The TID is unique and will stay the same as long as your USB serial port
device plugs into the same USB topology (same ports, same hubs, same
connections, etc.). This way it is possible for tio to successfully reconnect
to the same device.

Connect automatically to first new appearing serial device:
```
$ tio --auto-connect new
```

Connect automatically to latest registered serial device:
```
$ tio --auto-connect latest
```

It is possible to use exclude options to affect which serial devices are
involved in the automatic connection strategy:
```
$ tio --auto-connect new --exclude-devices "/dev/ttyACM?,/dev/ttyUSB2"
```

And to exclude drivers by pattern:
```
$ tio --auto-connect new --exclude-drivers "cdc_acm,ftdi_sio"
```
Note: Pattern matching supports '*' and '?'. Use comma separation to define
multiple patterns.

To include drivers by specific pattern simply negate the exclude option:
```
$ tio --auto-connect new --exclude-drivers !("cp2102")
```

Log to file with autogenerated filename:
```
$ tio --log /dev/ttyUSB0
```

Log to file with specific filename:
```
$ tio --log --log-file my-log.txt
```

Enable ISO8601 timestamps per line:
```
$ tio --timestamp --timestamp-format iso8601 /dev/ttyUSB0
```

Output to hex with width 16:
```
$ tio --output-mode hex16 /dev/ttyUSB0
```

Redirect I/O to IPv4 network socket on port 4242:
```
$ tio --socket inet:4242 /dev/ttyUSB0
```

Map NL to CR-NL on input from device and DEL to BS on output to device:
```
$ tio --map INLCRNL,ODELBS /dev/ttyUSB0
```

Pipe data to the serial device:
```
$ cat data.bin | tio /dev/ttyUSB0
```

Manipulate modem lines on connect:
```
$ tio --script "tio.set{DTR=high,RTS=low}; tio.msleep(100); tio.set{DTR=toggle,RTS=toggle}" /dev/ttyUSB0
```

Pipe command to serial device and wait for line response within 1 second:
```
$ echo "*IDN?" | tio /dev/ttyACM0 --script "tio.expect('\r\n', 1000)" --mute
KORAD KD3305P V4.2 SN:32475045
```

### 3.2 Key commands

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

```
[15:02:53.269] Key commands:
[15:02:53.269]  ctrl-t ?       List available key commands
[15:02:53.269]  ctrl-t b       Send break
[15:02:53.269]  ctrl-t c       Show configuration
[15:02:53.269]  ctrl-t e       Toggle local echo mode
[15:02:53.269]  ctrl-t f       Toggle log to file
[15:02:53.269]  ctrl-t F       Flush data I/O buffers
[15:02:53.269]  ctrl-t g       Toggle serial port line
[15:02:53.269]  ctrl-t i       Toggle input mode
[15:02:53.269]  ctrl-t l       Clear screen
[15:02:53.269]  ctrl-t L       Show line states
[15:02:53.269]  ctrl-t m       Change mapping of characters on input or output
[15:02:53.269]  ctrl-t o       Toggle output mode
[15:02:53.269]  ctrl-t p       Pulse serial port line
[15:02:53.269]  ctrl-t q       Quit
[15:02:53.269]  ctrl-t r       Run script
[15:02:53.269]  ctrl-t R       Execute shell command with I/O redirected to device
[15:02:53.269]  ctrl-t s       Show statistics
[15:02:53.269]  ctrl-t t       Toggle line timestamp mode
[15:02:53.269]  ctrl-t v       Show version
[15:02:53.269]  ctrl-t x       Send file via Xmodem
[15:02:53.269]  ctrl-t y       Send file via Ymodem
[15:02:53.269]  ctrl-t ctrl-t  Send ctrl-t character
```

If needed, the prefix key (ctrl-t) can be remapped via configuration file.

### 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/config
 - $HOME/.config/tio/config
 - $HOME/.tioconfig

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

### 3.3.1 Example

Example configuration file:

```
[default]
baudrate = 115200
databits = 8
parity = none
stopbits = 1
color = 10

[rpi3]
device = /dev/serial/by-id/usb-FTDI_TTL232R-3V3_FTGQVXBL-if00-port0
no-reconnect = true
log = true
log-file = rpi3.log
line-pulse-duration = DTR=200,RTS=150
color = 11

[svf2]
device = /dev/ttyUSB0
baudrate = 9600
script = tio.expect("login: "); tio.write("root\n"); tio.expect("Password: "); tio.write("root\n")
color = 12

[esp32]
device = /dev/serial/by-id/usb-0403_6014-if00-port0
script = tio.set{DTR=high,RTS=low}; tio.msleep(100); tio.set{DTR=low,RTS=high}; tio.msleep(100); tio.set{RTS=low}
script-run = once
color = 13

[usb-devices]
pattern = ^usb([0-9]*)
device = /dev/ttyUSB%m1
color = 14
```

To use a specific profile by name simply start tio like so:
```
$ tio rpi3
```
Or by pattern match:
```
$ tio usb12
```

Another more elaborate configuration file example is available [here](examples/config/config).

### 3.4 Lua script API

Tio suppots Lua scripting to easily automate interaction with the tty device.

In addition to the standard Lua API tio makes the following functions
and variables available:


#### `tio.expect(pattern, timeout)`

Waits for the Lua pattern to match or timeout before continuing.
Timeout is in milliseconds, defaults to 0 meaning it will wait forever.

Returns the captures from the pattern or `nil` on timeout.

#### `tio.read(size, timeout)`

Read up to `size` bytes from serial device. If timeout is 0 or not provided it
will wait forever until data is ready to read.

Returns a string up to `size` bytes long on success and `nil` on timeout.

#### `tio.readline(timeout)`

Read line from serial device. If timeout is 0 or not provided it will wait
forever until data is ready to read.

Returns a string on success and `nil` on timeout.  On timeout a partially read
line may be returned as a second return value.

#### `tio.write(string)`

Write string to serial device.

Returns the `tio` table.

#### `tio.send(file, protocol)`

Send file using x/y-modem protocol.

Protocol can be any of `XMODEM_1K`, `XMODEM_CRC`, `YMODEM`.

#### `tio.ttysearch()`

Search for serial devices.

Returns a table of number indexed tables, one for each serial device found.
Each of these tables contains the serial device information accessible via the
following string indexed elements "path", "tid", "uptime", "driver",
"description".

Returns `nil` if no serial devices are found.

#### `tio.set{line=state, ...}`
Set state of one or multiple tty modem lines.

Line can be any of `DTR`, `RTS`, `CTS`, `DSR`, `CD`, `RI`

State is `high`, `low`, or `toggle`.

#### `tio.sleep(seconds)`

Sleep for seconds.

#### `tio.msleep(ms)`

Sleep for milliseconds.

#### `tio.alwaysecho`

A boolean value, defaults to `true`.

If `tio.alwaysecho` is `false`, the result of `tio.read`, `tio.readline` or
`tio.expect` will only be returned from the function and not logged or printed.

If `tio.alwaysecho` is set to `true`, reading functions also emit a single
timestamp to stdout and log file per `options.timestamp` and `options.log`.


## 4. Installation

### 4.1 Installation using package manager (Linux)

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 its package maintainers team.

### 4.2 Installation using snap (Linux)

Install latest stable version:
```
$ snap install tio --classic
```

Note: Classic confinement is currently required due to limitations of the snapcraft framework.
See [Issue #187](https://github.com/tio/tio/issues/187) for discussion.

### 4.3 Installation using brew (MacOS, Linux)

If you have [brew](http://brew.sh) installed:
```
$ brew install tio
```

### 4.4 Installation using MSYS2 (Windows)

If you have [MSYS2](https://www.msys2.org) installed:
```
$ pacman -S tio
```

### 4.5 Installation from source

The latest source releases can be found [here](https://github.com/tio/tio/releases).

Before running the install steps make sure you have glib and lua libraries installed. For example:

```
$ sudo apt install libglib2.0-dev liblua5.2-dev
```

Install steps:
```
$ meson setup build
$ meson compile -C build
$ meson install -C build
```

See meson\_options.txt for tio specific build options.

Note: The meson install steps may differ depending on your specific system.

### 4.6 Known issues

Getting permission access errors trying to open your serial device?

Add your user to the group which allows serial device access permanently. For example, to add your user to the 'dialout' group do:
```bash
sudo usermod -a -G dialout <username>
```
Switch to the "dialout" group, temporary but immediately for this session.
```bash
newgrp dialout
```


## 5. Contributing

This is an open source project - 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:

[![Donate](images/paypal.png)](https://www.paypal.me/lundmar)


## 6. Support

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


## 7. Website

Visit [tio.github.io](https://tio.github.io)


## 8. License

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


## 9. Authors

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

See the AUTHORS file for full list of contributors.
