linux terminal freezes script output when it is run as systemd script after some time-CodePudding

I'm just writing a program which should run on linux main terminal TTY1 as a "more interactive" replacement for plymouth.

Everthing is ok. After one hour or two, the display freezed until any keystroke is pressed, lets for example assume that I run a bash loop which is displaying time, its gone after some time and only displays last iteration when some timeout occured.

My service:

[Unit]
Description=Script starter
After=getty.target
[email protected]

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/bin/screen.sh
StandardInput=tty-force

[Install]
WantedBy=multi-user.target

and script:

#!/bin/bash

while true
do
    sleep 1
    clear
    date
done

the same issue is when I run program I wroted in c/ncurses

CodePudding user response：

With your information so far, it is hard so say why there is a freeze. Maybe you switch tty and there isn't enough RAM after "one or two hours". Maybe you have a defect hardware (graphic card, cpu, ram). Maybe, maybe...

Try to write your sdtout in a file and read it with tail.

#!/bin/bash
clear
while true
do
    sleep 1
    date >> logFile
done

And in another console try this:

tail -f --retry logfile

-f stands for follow

--retry if the file is not available, it will retry to read it.

CodePudding user response：

I was looking whole day, what causes that console screen freezes displaying dead timer and I found cause.

the kernel parameter consoleblank, I set to 0 and reinstall grub, after that its working

Idk, how its behaves on normal pc, I was using virtual console offered by vsphere

so yest consoleblank=0 grub reinstall