Bash shell script for macOS which detects and lists USB-connected serial devices

dlist.sh

#!/bin/bash

# Save script as `dlist` at a location on your $PATH.
# Run `chmod +x /path/to/dlist`
#
# Connect a USB serial device, eg. a Raspberry Pi Pico, and then
# enter `dlist` at the command line.
#
# You should see something like:
# `/dev/cu.usbserial-01AB8E0B`
#
# If you have only one device attached, you can include the function's
# output in other command line call. For example:
#
# `pyboard -d $(dlist) -f cp prefs.json :prefs.json`
#
# If you have multiple devices attached, `dlist` will list them all:
#
# `1. /dev/cu.usbmodem1101
#  2. /dev/cu.usbserial-01AB8E0B`
#
# You can then specify a single device by number. For example:
#
# `pyboard -d $(dlist 2) -f cp prefs.json :prefs.json`
#
# NOTE Requires macOS

devices=($(/bin/ls /dev/cu.usb* 2>/dev/null))
if [[ ${#devices[@]} -gt 0 ]]; then
    if [[ ${#devices[@]} -eq 1 ]]; then
        echo ${devices}
    else
        count=1
        for device in "${devices[@]}"; do
            if [[ -n "$1" && "$1" == ${count} ]]; then
                echo ${device}
            elif [[ -z "$1" ]]; then
                echo "${count}. ${device}"
            fi
            ((count+=1))
        done
    fi
fi