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Worknotes

:bulb: A single roundup of the Linux serial terminal programs you use to reach the console port of network devices (switches/routers) or embedded boards over a USB-serial cable — overview, install, usage (start/stop), pros/cons, and removal.

Environment: Ubuntu 22.04+ / USB-to-Serial console cable (FTDI, PL2303, etc.)

[01] Overview — What Is a Serial Terminal

A network device’s Console port is a path to the CLI that works even without an IP. When you connect a USB-serial cable to the PC, Linux usually exposes it as:

  • /dev/ttyUSB0 — USB-Serial converter chips like FTDI, PL2303
  • /dev/ttyACM0 — CDC-ACM family (USB built into some boards)

A “serial terminal” is a program that opens this device and communicates using serial parameters such as baud rate (e.g. 9600). The main ones are screen, minicom, picocom, and tio.

:warning: A regular user may lack serial-port access and hit Permission denied. Add your user to the dialout group to connect without sudo (re-login required).



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# Identify the device
ls -l /dev/ttyUSB* /dev/ttyACM* 2>/dev/null
dmesg | grep -iE 'ttyUSB|ttyACM' | tail   # device name at plug-in time
lsusb                                       # check the serial chip (FTDI/Prolific)

# Grant access (once, then log out → log in)
sudo usermod -aG dialout $USER

All examples below assume 9600 8N1, no flow control (the default for Arista and similar network devices). Just change the baud to match your device.

[02] screen

The most widely preinstalled, all-purpose “just connect” tool. Not serial-specific, but supports serial.



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# Install
sudo apt update && sudo apt install -y screen

# Start: screen <device> <baud>
screen /dev/ttyUSB0 9600
  • After starting: if the screen is blank, press Enter to wake the prompt.
  • Quit: Ctrl + a then k → y (force-kill the session).
  • Detach (keep in background): Ctrl + a then d; reattach with screen -r.

[03] minicom

A serial-dedicated program. Saves settings via menus and provides file transfer (X/Y/Zmodem) and logging.



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# Install
sudo apt install -y minicom

# Start: specify device/baud directly
sudo minicom -D /dev/ttyUSB0 -b 9600

# Settings menu (persistent)
sudo minicom -s
  • In Serial port setup, set Serial Device (/dev/ttyUSB0), Bps/Par/Bits (9600 8N1), Hardware/Software Flow Control (No) → Save setup as dfl.
  • Quit: Ctrl + a then x → Yes.

[04] picocom

As the name suggests, lightweight with clear command-line options — great for scripts/automation. Almost no UI features.



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# Install
sudo apt install -y picocom

# Start
picocom -b 9600 /dev/ttyUSB0
  • Quit: Ctrl + a then Ctrl + x.
  • All other shortcuts use the Ctrl + a prefix.

[05] tio (Recommended)

A modern serial terminal. Clean command line and auto-reconnect when the device is unplugged and plugged back in — the most convenient option when you attach to device consoles often.



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# Install (default repos on Ubuntu 22.04+)
sudo apt install -y tio

# Start: tio defaults to 115200, so specify 9600
tio -b 9600 /dev/ttyUSB0
  • Quit: Ctrl + t then q (all shortcuts use the Ctrl + t prefix).
  • List shortcuts: Ctrl + t then ?.
  • Save a profile: register it in ~/.config/tio/config to connect by name.


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# ~/.config/tio/config — connect with "tio arista"
[arista]
device = /dev/ttyUSB0
baudrate = 9600

[06] (Reference) cu / putty

  • cu: sudo apt install -y cu → cu -l /dev/ttyUSB0 -s 9600, quit with ~.. An old UUCP-era tool for simple uses.
  • putty: has GUI/CLI versions on Linux too. putty -serial /dev/ttyUSB0 -sercfg 9600. The tools above are nicer in a console environment, though.

[07] Pros and Cons

Program Pros Cons Best for
screen Preinstalled almost everywhere, simple Lacks serial-specific features, confusing exit keys, awkward logging Quick, ad-hoc console access on someone else’s server
minicom Serial-dedicated, saves settings, logging/file transfer Fiddly initial setup UI When you need features like file transfer
picocom Lightweight, clear options, good for automation Almost no UI features Cleanly viewing a console from a script
tio Modern, auto-reconnect, profiles Sometimes not preinstalled Attaching to your own device consoles often (personal pick)
putty Familiar in GUI Awkward in a server CLI GUI access on Ubuntu Desktop

For attaching to network-device consoles from your own PC: tio → picocom → screen → minicom.

  • Your device / used often → tio (auto-reconnect and profiles are decisive)
  • Ad-hoc / on-site / someone else’s server (install rights unclear) → screen (already everywhere)
  • Need file transfer → minicom

In short: “tio for your own setup, screen for ad-hoc” — those two axes are enough.

[08] Removal



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# Remove individually
sudo apt remove -y screen
sudo apt remove -y minicom
sudo apt remove -y picocom
sudo apt remove -y tio

# Fully remove including config files (purge)
sudo apt purge -y minicom

# Clean up dependencies
sudo apt autoremove -y
  • remove deletes the package only; purge also removes config files under /etc.
  • User settings (~/.config/tio/, ~/.minirc.dfl, etc.) must be deleted manually.


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rm -f ~/.minirc.dfl              # minicom user settings
rm -rf ~/.config/tio             # tio profiles

[09] Summary

Step Command
Identify device ls /dev/ttyUSB*, dmesg \| grep ttyUSB, lsusb
Permission sudo usermod -aG dialout $USER (re-login)
screen screen /dev/ttyUSB0 9600 / quit Ctrl+a k
minicom minicom -D /dev/ttyUSB0 -b 9600 / quit Ctrl+a x
picocom picocom -b 9600 /dev/ttyUSB0 / quit Ctrl+a Ctrl+x
tio tio -b 9600 /dev/ttyUSB0 / quit Ctrl+t q
Removal sudo apt remove/purge <pkg> + autoremove

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