If statement in Bash

[borgvall]

I'm trying to make a script which should set the correct color profile for the screen that is being used. It's not working even after several hours of trial and error. So please help me out with this code.



#!/bin/bash
grafik=xrandr | head -1
screen0="Screen 0: minimum 320 x 240, current 1920 x 1200, maximum #1920 x 1200"
screen1="Screen 1: minimum 320 x 240, current 1280 x 800, maximum 1280 x 800"
if [ "$grafik" = "$screen0" ];
then
xcalib /usr/share/color/icc/Monitor_2008-03-27_2_Benq_brightness30.icc
else [ "$grafik" = "$screen1" ];
xcalib /usr/share/color/icc/Monitor_2008-03-27_3_m1330_luminance195.icc
fi

[geirha]

You want the first line of xrandr to be stored in grafik, you need to use the backticks for that:

grafik=`xrandr | head -1`
# alternatively you can use $() the same way
grafik=$(xrandr | head -1)

EDIT: Also, you probably only need to check if the first part is "Screen 0" or "Screen 1":


grafik=`xrandr | head -1`

case "$grafik" in
"Screen 0"*)
echo "Screen 0 stuff"
;;
"Screen 1"*)
echo "Screen 1 stuff"
;;
*)
echo no match
;;
esac

[SeanHodges]

$grafik is getting set incorrectly.

Use back-ticks to pass the output of your command into $grafik:

grafik=`xrandr | head -1`


Edit: geirha beat me to it :)

[borgvall]

Ah, I read some tutorials on this but thought that the backsticks just were ' but in another character type.

[geirha]

I was too slow on editing my previous post, have a look at the example I added there. Your else is also wrong, instead of else [ "$grafik" = "$screen1" ]; you want to use
elif [ "$grafik" = "$screen1" ]; then with elif being short for else if.

[borgvall]

I noticed that what counts as screen 0 varies, therefore "minimum 320 x 240, current 1920 x 1200, maximum #1920 x 1200" and "minimum 320 x 240, current 1280 x 800, maximum 1280 x 800" are the things which shows if the external or the internal screen should be used. This force me to make the script look for those lines and not only compare the exact line which "xrandr | head -1" outputs. So I guess I need help with another operator.

[dwhitney67]

When implementing an if-statement, is not the semi-colon optional? Well, not if the "then" statement is on the same line. But if the "then" is on a separate line, the semi-colon should not be present. At least I think so; I could be wrong.

Semi-colon needed:


if [ some-condition ]; then
...
fi


Semi-colon not needed:


if [ some-condition ]
then
...
fi

[borgvall]

Ok, but that isn't the problem Please see my previous post, I hope it's possible to understand it.

[SeanHodges]

I noticed that what counts as screen 0 varies, therefore "minimum 320 x 240, current 1920 x 1200, maximum #1920 x 1200" and "minimum 320 x 240, current 1280 x 800, maximum 1280 x 800" are the things which shows if the external or the internal screen should be used. This force me to make the script look for those lines and not only compare the exact line which "xrandr | head -1" outputs. So I guess I need help with another operator.

Perhaps this?


screen0="Screen 0"
screen1="Screen 1"
if [[ "$grafik" =~ "$screen0" ]]
then
...
elif [[ "$grafik" =~ "$screen1" ]]
then
...
fi

Also, check out geirha's "switch case" post earlier.

[akvino]

does [[ "$a" =~ "$b" ]] check for bitwise equality?

[mssever]

does [[ "$a" =~ "$b" ]] check for bitwise equality?
No, =~ expects a regular expression on the right hand side and tests the left hand side for a match.

[geirha]

does [[ "$a" =~ "$b" ]] check for bitwise equality?

It matches regular expressions. Sort of like doing echo "$a" | egrep "$b".

[borgvall]

Perhaps this?


screen0="Screen 0"
screen1="Screen 1"
if [[ "$grafik" =~ "$screen0" ]]
then
...
elif [[ "$grafik" =~ "$screen1" ]]
then
...
fi

Also, check out geirha's "switch case" post earlier.

That was a good idea but this doesn't work from what I think because Screen 0 and Screen 1 changes when I unplug the external monitor. So again, what has to be compared is what's written after "Screen X:"

This is what I tried last time:


grafik=`xrandr | head -1`
screen0="minimum 320 x 240, current 1920 x 1200, maximum #1920 x 1200"
screen1="minimum 320 x 240, current 1280 x 800, maximum 1280 x 800"
if [[ "$grafik" =~ "$screen0" ]]
then
/home/victor/dokument/diverse/script/Benq.icc.sh
elif [[ "$grafik" =~ "$screen1" ]]
then
/home/victor/dokument/diverse/script/XPS.bright.icc.sh
fi

[borgvall]

That was a good idea but this doesn't work from what I think because Screen 0 and Screen 1 changes when I unplug the external monitor. So again, what has to be compared is what's written after "Screen X:"

This is what I tried last time:


grafik=`xrandr | head -1`
screen0="minimum 320 x 240, current 1920 x 1200, maximum #1920 x 1200"
screen1="minimum 320 x 240, current 1280 x 800, maximum 1280 x 800"
if [[ "$grafik" =~ "$screen0" ]]
then
/home/victor/dokument/diverse/script/Benq.icc.sh
elif [[ "$grafik" =~ "$screen1" ]]
then
/home/victor/dokument/diverse/script/XPS.bright.icc.sh
fi


By the way that Benq.icc.sh and XPS.bright.icc.sh run xcalib and the icc file.

[geirha]

That was a good idea but this doesn't work from what I think because Screen 0 and Screen 1 changes when I unplug the external monitor. So again, what has to be compared is what's written after "Screen X:"

This is what I tried last time:


grafik=`xrandr | head -1`
screen0="minimum 320 x 240, current 1920 x 1200, maximum #1920 x 1200"
screen1="minimum 320 x 240, current 1280 x 800, maximum 1280 x 800"
if [[ "$grafik" =~ "$screen0" ]]
then
/home/victor/dokument/diverse/script/Benq.icc.sh
elif [[ "$grafik" =~ "$screen1" ]]
then
/home/victor/dokument/diverse/script/XPS.bright.icc.sh
fi

It sounds like you just need to check the maximum value. If so, I'd use a case like this


case "`xrandr | head -1`" in
*"1920 x 1200") /home/victor/dokument/diverse/script/Benq.icc.sh ;;
*"1280 x 800") /home/victor/dokument/diverse/script/XPS.bright.icc.sh ;;
*)
echo "no matching screen" >&2
exit 1
;;
esac

[borgvall]

It sounds like you just need to check the maximum value. If so, I'd use a case like this


case "`xrandr | head -1`" in
*"1920 x 1200") /home/victor/dokument/diverse/script/Benq.icc.sh ;;
*"1280 x 800") /home/victor/dokument/diverse/script/XPS.bright.icc.sh ;;
*)
echo "no matching screen" >&2
exit 1
;;
esac


Thank you Geirha!