Bash question

bl0ndynek · 2014-10-12 18:07:25

Hi,

I have question about two lines from https://wiki.archlinux.org/index.php/Acpid

 
echo $(($(< $bl_dev/brightness) - $step)) >$bl_dev/brightness

I have question about this part

$($(<

why it is like that?

lucke · 2014-10-12 18:40:04

"< file" is input redirection and works somewhat similarly to "cat file". $() executes the command and returns its output. $(()) can be used for counting.

bl0ndynek · 2014-10-12 19:31:30

Thank you now it's clear.

Awebb · 2014-10-12 19:33:08

You might want to have a look at the guides at tldp.org.

jasonwryan · 2014-10-12 19:38:57

Awebb wrote:

You might want to have a look at the guides at http://mywiki.wooledge.org/

FTFY.

Awebb · 2014-10-12 19:56:54

Indeed! If one does not have the information, the other will!

Arch Linux

#1 2014-10-12 18:07:25

Bash question

#2 2014-10-12 18:40:04

Re: Bash question

#3 2014-10-12 19:31:30

Re: Bash question

#4 2014-10-12 19:33:08

Re: Bash question

#5 2014-10-12 19:38:57

Re: Bash question

#6 2014-10-12 19:56:54

Re: Bash question

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