Autorun a script at boot

alphalpha · 2018-11-14 20:47:39

Hey Guys,
i want to run a script each time my computer boots up

problem is since i compiled a new kernel, my screen backlight will go very dark once open-rc starts booting up
i tried the bootloader thing that people suggest on the internet but it only works randomly sometimes

so i wrote this short script that i want to execute with root rights during startup

brightness="/sys/class/backlight/intel_backlight/brightness"
if [[ -f $brightness ]] && [[ "$(cat $brightness)" != "3000" ]]; then
tee $brightness <<< 3000
fi

i tried to add it into /etc/rc.local but that does nothing...
any ideas how to make it work?

yeti · 2018-11-14 22:46:22

Translate all BASHisms to standard SH because:

$ head -1 /etc/rc.local 
#!/bin/sh -e

arnaiz · 2018-11-15 00:22:31

For me that script its fine, so try to guest when and who are running /etc/rc.local

I suggest put something like this on your /etc/rc.local to debug your startup:

date >> /var/log/rc.local.test

if the file its not created, maybe its because /etc/rc.local hasnt execution permissions.

yeti · 2018-11-15 00:37:30

(yeti@kumari:23)/tmp$ cat -n meep.sh 
     1  #!/bin/sh -e
     2  
     3  if [[ 1 = 1 ]] ; then
     4          echo 'boo!'
     5  fi
     6  
     7  tee <<< Moo.
(yeti@kumari:23)/tmp$ ./meep.sh 
./meep.sh: 3: ./meep.sh: [[: not found
./meep.sh: 7: ./meep.sh: Syntax error: redirection unexpected

arnaiz · 2018-11-15 00:51:02

#!/bin/sh -e

It seems there is the problem, I was running under bash.

alphalpha · 2018-11-15 11:25:40

Translate all BASHisms to standard SH because:

I tried it with just

brightness="/sys/class/backlight/intel_backlight/brightness"
tee $brightness <<< 3000

but that didn't work, i guess im terrible with SH

anyway i solved the problem by changing the rc.local from #!/bin/sh -e to #!/usr/bin/zsh
thx guys

ilargi · 2018-11-15 11:38:49

Try this:

brightness="/sys/class/backlight/intel_backlight/brightness"
if [ -f $brightness ] && [ "$(cat $brightness)" != "3000" ]; then
        echo 3000 > $brightness

fi

Edit: Corrected code error.

Last edited by ilargi (2018-11-15 12:29:35)

yeti · 2018-11-15 11:45:54

Try...

echo 3000 > $brightness

Such "tee" tricks typically are used because "sudo echo something >somewhere" still does the output redirection as the calling user because the redirection is done before "sudo" is run. "sudo tee somewhere" writes with "root" rights to "somewhere" because "tee" opens "somewhere" and that happens with "root" superpowers due to "sudo". This all does not really matter in "rc.local" because the whole script already runs with "root" rights.

Switching the interpreter of "rc.local" to "/usr/bin/zsh" is not a good idea because "zsh" is not an essential package. System scripts should use "/bin/sh".

But ok: It's your system.

yeti · 2018-11-15 11:51:49

ilargi wrote:

Try this:

brightness="/sys/class/backlight/intel_backlight/brightness"
if [ -f $brightness ] && [ "$(cat $brightness)" != "3000" ]; then
	tee $brightness 3000
fi

	tee $brightness 3000

...will wait for input instead of writing "3000" to the desired location. And create a file named "3000".

Can you please try your code before publishing it?

ilargi · 2018-11-15 12:31:27

I stand corrected.
Changed code in original message.

yeti · 2018-11-15 14:06:12

ilargi wrote:

Changed code in original message.

Thanks!

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#1 2018-11-14 20:47:39

Autorun a script at boot

#2 2018-11-14 22:46:22

Re: Autorun a script at boot

#3 2018-11-15 00:22:31

Re: Autorun a script at boot

#4 2018-11-15 00:37:30

Re: Autorun a script at boot

#5 2018-11-15 00:51:02

Re: Autorun a script at boot

#6 2018-11-15 11:25:40

Re: Autorun a script at boot

#7 2018-11-15 11:38:49

Re: Autorun a script at boot

#8 2018-11-15 11:45:54

Re: Autorun a script at boot

#9 2018-11-15 11:51:49

Re: Autorun a script at boot

#10 2018-11-15 12:31:27

Re: Autorun a script at boot

#11 2018-11-15 14:06:12

Re: Autorun a script at boot

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