Z Shell function for macOS which detects and lists USB-connected serial devices

dlist.zsh

# Add to your `.zshrc` file or use the function's contents as a script.
#
# With the former, add the function, restart your terminal, connect
# a USB serial device, eg. a Raspberry Pi Pico, and then enter `dlist`
# at the command line. 
#
# You should see something like this:
# `/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

dlist() {
    local devices=($(/bin/ls /dev/cu.usb* 2>/dev/null))
    if [[ ${#devices} -gt 0 ]]; then
        if [[ ${#devices} -eq 1 ]]; then
            echo ${devices}
        else
            local 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
}