如何將指令從控制台 shell 腳本 (ssh) 導向到 xserver

Question

我正在嘗試從樹莓派上運行的 xserver 獲取值。該命令DISPLAY=:0 xssstate -i在命令列中起作用，但在運行腳本時不起作用。

在本地運行腳本效果很好，但是當透過 ssh 運行它時卻不行

腳本：

enter code here

#!/bin/bash

# Wanted trigger timeout in milliseconds.
IDLE_TIME=$((10*1000))

triggered=0

while [ 1 -eq 1 ]
do
sleep 1
sstime=$(DISPLAY=:0 xssstate -i)
echo "idletime $IDLE_TIME"
echo "sstime $sstime"
if [ "$sstime" -gt "$IDLE_TIME" ] || [ "$triggered" -eq 0 ]
then
        echo 235 > /sys/waveshare/rpi_backlight/brightness
        triggered=1
elif [ "$sstime" -lt "$IDLE_TIME" ] || [ "$triggered" -eq 1 ]
then
        echo 0 > /sys/waveshare/rpi_backlight/brightness
        triggered=0
else
        triggered=0
fi

done

輸出：

No protocol specified
Cannot open display.
idletime 10000
sstime
./backLTctrl.sh: line 15: [: : integer expression expected
No protocol specified
Cannot open display.
idletime 10000
sstime
./backLTctrl.sh: line 15: [: : integer expression expected
./backLTctrl.sh: line 19: [: : integer expression expected
No protocol specified
Cannot open display.
idletime 10000
sstime
./backLTctrl.sh: line 15: [: : integer expression expected
No protocol specified
Cannot open display.
idletime 10000
sstime
./backLTctrl.sh: line 15: [: : integer expression expected
./backLTctrl.sh: line 19: [: : integer expression expected