tcler's blog --- 其实我是一个程序员
Show me your flowcharts and conceal your tables, and I shall continue to be mystified. Show me your tables, and I won’t usually need your flowcharts; they’ll be obvious.

In computing, Virtual Network Computing (VNC) is a graphical desktop-sharing system that uses the 
Remote Frame Buffer protocol (RFB) to remotely control another computer. 
It transmits the keyboard and mouse events from one computer to another, relaying the **graphical-screen** 
updates back in the other direction, over a network.

vncget() {
        local _vncaddr=$1

        [[ -z "$_vncaddr" ]] && return 1
        vncdo -s ${_vncaddr} capture $Rundir/_screen.png
        gm convert $Rundir/_screen.png  -threshold 30%  $Rundir/_screen2.png
        gocr -i $Rundir/_screen2.png 2>/dev/null
}

vncput() {
        local vncport=$1
        shift

        which vncdo >/dev/null || {
                echo "{WARN} could not find command 'vncdo'" >&2
                return 1
        }

        [[ -n "$*" ]] && echo -e "\033[1;33m[vncput>$vncport] $*\033[0m"

        local msgArray=()
        for msg; do
                if [[ -n "$msg" ]]; then
                        if [[ "$msg" = key:* ]]; then
                                msgArray+=("$msg")
                        else
                                regex='[~@#$%^&*()_+|}{":?><!]'
                                _msg="${msg#type:}"
                                if [[ "$_msg" =~ $regex ]]; then
                                        while IFS= read -r line; do
                                                [[ "$line" =~ $regex ]] || line="type:$line"
                                                msgArray+=("$line")
                                        done < <(sed -r -e 's;[~!@#$%^&*()_+|}{":?><]+;&\n;g' -e 's;[~!@#$%^&*()_+|}{":?><];\nkey:shift-&;g' <<<"$_msg")
                                else
                                        msgArray+=("$msg")
                                fi
                        fi
                        msgArray+=("")
                else
                        msgArray+=("$msg")
                fi

        done
        for msg in "${msgArray[@]}"; do
                if [[ -n "$msg" ]]; then
                        if [[ "$msg" = key:* ]]; then
                                vncdo -s $vncport key "${msg#key:}"
                        else
                                vncdo -s $vncport type "${msg#type:}"
                        fi
                else
                        sleep 1
                fi
        done
}
vncputln() {
        vncput "$@" "key:enter"
}

ocrgrep() {
        local pattern=$1
        local ignored_charset=${2:-ijkfwe[|:}
        pattern=$(sed "s,[${ignored_charset}],.,g" <<<"${pattern}")
        grep -i "${pattern}"
}

vncwait() {
        local addr=$1
        local pattern="$2"
        local tim=${3:-1}
        local ignored_charset="$4"

        echo -e "\n=> waiting: \033[1;36m$pattern\033[0m prompt ..."
        while true; do vncget $addr | ocrgrep "$pattern" "$ignored_charset" && break; sleep $tim; done
}