leftright

#!/bin/bash
# Switch mouse buttons to left- or right-handed.

# Usage: left <xinput id>
left() {
    xinput --set-button-map $1 3 2 1 4 5 6 7 8 9
}

# Usage: right <xinput id>
right() {
    xinput --set-button-map $1 1 2 3 4 5 6 7 8 9
}

# Prints mice one per line using a format:
# <name>TAB<xinput id>
list_pointing_devices() {
    xinput --list |
    sed 's/[^A-Za-z0-9= 	]//g' |
    sed 's/^ *//' |
    awk -F ' *	 *' '$3 ~ / pointer / {
        gsub(/^id=/, "", $2)
        printf "%s\t%s\n", $1, $2
    }'
}

# Symlinks called "left" and "right" determine which button map to use.
handedness=$(basename $0)
case $handedness in left|right)
    ;;
*)
    printf 'Must be invoked via a symlink called "left" or "right"\n' >&2
    exit 1
esac

# All mice, but not trackpads.
if test "$1" = "mice"; then
    list_pointing_devices |
    while IFS=$'\t' read -r name id; do
        case "$name" in *"Mouse"|"Logitech M"*)
            echo "$name"
            $handedness "$id";;
        esac
    done
    exit
fi

printf "Found the following pointing devices:\n"
list_pointing_devices |
while IFS=$'\t' read -r name id; do
    printf '%s (%d)\n' "$name" "$id"
done
printf "Enter the number of the device to make $handedness-handed: "
read -r id
if test -n "$id"; then
    $handedness "$id"
fi