redshifter

#!/bin/bash

#----------------------------------------------------------------------------------
# Project Name      - miscellaneous/redshifter
# Started On        - Tue  3 Oct 19:14:37 BST 2017
# Last Change       - Mon 26 Mar 20:33:19 BST 2018
# Author E-Mail     - terminalforlife@yahoo.com
# Author GitHub     - https://github.com/terminalforlife
#----------------------------------------------------------------------------------
# Effective and simple tool to manually adjust the gamma via Redshift.
#
# IMPORTANT:
#
# This small script assumes you have redshift (and mkdir of course) installed and
# available. Also assumed is that you'll be using this script via keyboard
# shortcuts, not terminals.
#
# Calling bash to avoid dependencies and to make use of bash syntax.
#
# SYNTAX:     redshifter [OPT]
#
# OPT:        --version|-v            - Output only the version datestamp.
#             --increment|-i N        - Increment gamma by N integer.
#             --decrement|-d N        - Decrement gamma by N integer.
#             --reset|-r              - Reset to the default.
#
# NOTE:       As of 2018-03-26, redshifter no longer uses /tmp for the temporary
#             file from which redshifter reads and sets the current value. This
#             will be stored in the user's home directory, to keep the value from
#             resetting upon reboot.
#
#             If you do need to reset the value, simply delete the stored file:
#
#               ~/.config/redshifter.tmp
#
#             If this won't work, when it previously may have, check the value
#             saved isn't a value of '-100' or something; must be an integer.
#----------------------------------------------------------------------------------

_VERSION_="2018-03-26"

BUFFER="$HOME/.config/redshifter.tmp"
[ -d "$HOME/.config" ] || /bin/mkdir "$HOME/.config"

if ! [ -f "$BUFFER" -a -r "$BUFFER" ]; then
	GAMMAS_NOW=6500
	printf "6500\n" > "$BUFFER"
else
	GAMMAS_NOW=`< "$BUFFER"`
fi

case "$1" in
	--version|-v)
		printf "%s\n" "$_VERSION_"
		exit 0 ;;
	--reset|-r)
		printf "6500\n" > "$BUFFER"
		/usr/bin/redshift -o -O 6500K ;;
	--increment|-i)
		TEMP=$(( GAMMAS_NOW + $2 ))
		[ $TEMP -gt 25000 ] && exit 0
		printf "%d\n" "$TEMP" > "$BUFFER"
		/usr/bin/redshift -o -O ${TEMP}K ;;
	--decrement|-d)
		TEMP=$(( GAMMAS_NOW - $2 ))
		[ $TEMP -lt 1000 ] && exit 0
		printf "%d\n" "$TEMP" > "$BUFFER"
		/usr/bin/redshift -o -O ${TEMP}K ;;
esac

# vim: ft=sh noexpandtab colorcolumn=84 tabstop=8 noswapfile nobackup