CODEWITHSUNDEEP
bashscriptingstdoutbackground-processpid
Sterling Butters
Sterling Butters

Reputation: 1175

Sending stdout to pts and terminating process that generates that stdout on user input to the pts

Really wasn't sure whether to post this in on the Unix SE or here but here goes:

I was trying to get fancy with the asciiquarium package (https://github.com/cmatsuoka/asciiquarium), trying to make it function like an actual screensaver based on idle time but I seem to have a problem once I send asciiquarium's stdout to /pts/2 (I think the script is calling multiple background tasks). I feel like I should be somehow storing the PID of the asciiquarium background task and then manually killing the task around activated=false. However, when I do that I end up with a seemingly circular logic in that sending asciiquarium stdout to pts/2 thereby makes the tty no longer idle (right?).

Anyway, how can I send the asciiquarium stdout to /dev/pts/2 and terminate it when user input is detected on dev/pts/2?

# pts=$(who am i | awk '{print $2}')
pts="pts/2"
echo $pts >> test.log
old=$(stat -c %Y /dev/$pts)
ct=0
activated=false

while true
do
        sleep 1s
        new=$(stat -c %Y /dev/$pts)
        if [[ $new -eq $old ]]   # If new and old ts are the same it means that pts is idle
        then
                ((ct++))
                echo "$ct" >> test.log
        else
                ct=0
                echo "Resetting count!" >> test.log
                activated=false
        fi

        if [[ $ct -gt 10 ]]
        then
                if ! $activated
                then
                        activated=true
                        echo "Activating!" >> test.log
                        asciiquarium > /dev/$pts &
                else
                        continue
                fi
        fi

        old=$new
done

Upvotes: 0

Views: 44

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