On Linux, get info about device nodes, given a device class and/or a device type and/or a vendor id and/or a product id

getdevnodes.sh

##################################################################################################
# Two bash functions to get info about device nodes in Linux.                                    #
# Feel free to use and share, respecting the below license. :)                                   #
#                                                                                                #
# Copyright © 2017 Fabio Alemagna                                                                #
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##################################################################################################

getDevNodes() {
    if [ -n "$1" ] && [ "$1" != "no_class" ]; then
        2>/dev/null find -L /sys/class/$1 -maxdepth 2 -mindepth 2 -name uevent -exec realpath "{}" +
    else
        find /sys/devices -name uevent
    fi | {        
        if [ -z "$1" ]; then
            readarray -t lines < <(find /sys/class -maxdepth 2 -mindepth 2 -type l -print -exec realpath "{}" +)

            local -i count=${#lines[@]} sys_dev=count/2 sys_class=0
            local -A classes
            
            while [ $sys_dev -lt $count ]; do
                    class="${lines[$sys_class]#/*/*/}"
                    class="${class%/*}"
                    classes["${lines[$sys_dev]}"]="$class"
                    
                    sys_dev+=1
                    sys_class+=1                    
            done
        fi

        readarray -t uevents
                    
        for u in "${uevents[@]}"; do       
            DEVNAME=; DEVTYPE=no_type; while IFS="=" read key value; do {
                [ "$key" = "DEVNAME" ] && DEVNAME=/dev/"$value" 
            } || {
                [ "$key" = "DEVTYPE" ] && DEVTYPE="$value"                 
            }; done < "$u"
            
            if [ -n "$DEVNAME" ]; then              
                path="${u%/uevent}"
                while [ "$path" != "/sys/devices" ] && ! [ -f "$path"/idVendor ]; do
                    path="${path%/*}"
                done
                    
                [ "$path" != "/sys/devices" ] && {
                    read readIdVendor < "$path"/idVendor
                    read readIdProduct < "$path"/idProduct
                } || {
                    readIdVendor=----
                    readIdProduct=----
                }
                       
                echo "${1:-${classes[${u%/uevent}]:-no_class}}" "$DEVTYPE" "$readIdVendor" "$readIdProduct" "$DEVNAME" 
            fi
        done
    } | grep "^${1:-[[:graph:]]\+} ${2:-[[:graph:]]\+} ${3:-....} ${4:-....}" | cat
}

getDevNodesLite() {
    if [ -n "$1" ]; then
        2>/dev/null find -L /sys/class/$1 -maxdepth 2 -mindepth 2 -name uevent -exec realpath "{}" +
    else
        find /sys/devices -name uevent
    fi | {
        if [ -n "$2" ]; then
            readarray -t uevents              
            
            for u in "${uevents[@]}"; do
                path="${u%/uevent}"
                while [ "$path" != "/sys/devices" ] && ! [ -f "$path"/idVendor ]; do
                    path="${path%/*}"
                done
                                
                [ "$path" != "/sys/devices" ] && read readValue < "$path"/idVendor && [ "$readValue" = "$2" ] && {
                    if [ -n "$idProduct" ]; then
                        read readValue < "$path"/idProduct && [ "$readValue" = "$3" ]
                    fi
                } && echo "$u"
            done
        else
            cat
        fi
    } | {
        readarray -t uevents              

        [ ${#uevents[@]} -gt 0 ] && sed -n 's,DEVNAME=\(.*\),/dev/\1,p' "${uevents[@]}"
    }
}