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| #!/usr/bin/env bash | |
| set -o errexit -o nounset -o pipefail | |
| declare -r NAME="toggle-redshift" | |
| # If user doesn't have write permission to /var/lock then the $NAME directory | |
| # with write permissions should be created beforehand. | |
| declare -r LOCK_FILE="/var/lock/$NAME/$NAME.lock" | |
| declare -r PERSISTENT_FILE="/tmp/$NAME.tmp" | |
| declare -ar LEVEL_TO_CLI=( | |
| "-t 5000:5000 -b 1" | |
| "-t 4000:4000 -b 1" | |
| "-t 3500:3500 -b 1" | |
| "-t 3000:3000 -b 1" | |
| "-t 2750:2750 -b 1" | |
| "-t 2500:2500 -b 1" | |
| "-t 2250:2250 -b 1" | |
| "-t 2000:2000 -b 1" | |
| "-t 1800:1800 -b 1" | |
| ) | |
| if (( $# != 1 )); then | |
| printf "Usage: $NAME LEVEL\n" | |
| exit 2 | |
| fi | |
| declare -ir LEVEL="${1-1}-1" | |
| if [ -z $LEVEL ]; then | |
| exit 2 | |
| fi | |
| if (($LEVEL >= "${#LEVEL_TO_CLI[@]}")); then | |
| exit 2 | |
| fi | |
| lock_level() { | |
| head -n1 -- "$PERSISTENT_FILE" | |
| } | |
| lock_pid() { | |
| tail -n1 -- "$PERSISTENT_FILE" | |
| } | |
| kill_redshift() { | |
| kill -- "$(lock_pid)" 2>/dev/null | true | |
| } | |
| off() { | |
| kill_redshift | |
| rm -- "$PERSISTENT_FILE" | |
| } | |
| maybe_off() { | |
| if [ -r "$PERSISTENT_FILE" ]; then | |
| off | |
| fi | |
| } | |
| on() { | |
| redshift $REDSHIFT_FLAGS ${LEVEL_TO_CLI[$LEVEL]} >/dev/null 2>/dev/null & | |
| PID="$!" | |
| printf -- "%s\n%s\n" "$LEVEL" "$PID" >"$PERSISTENT_FILE" | |
| sleep 0.1 | |
| } | |
| off_and_on() { | |
| kill_redshift | |
| on | |
| } | |
| main() { | |
| flock -x $LOCK_FD | |
| if (( $LEVEL < 0 )); then | |
| maybe_off | |
| elif [ -r "$PERSISTENT_FILE" ]; then | |
| if (( "$(lock_level)" == $LEVEL )); then | |
| off | |
| else | |
| off_and_on | |
| fi | |
| else | |
| on | |
| fi | |
| flock -u $LOCK_FD | |
| } | |
| mkdir -v -p -- "$(dirname -- "$LOCK_FILE")" | |
| declare -r LOCK_FD="9" | |
| main 9>"$LOCK_FILE" |
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