disk space notification script. tested in debian 10

check_disk_space_and_notificate.sh

#ref: https://pc.casey.jp/archives/153903095

##!/bin/sh

#host_name="<your host>"
#message_tag="[WARNING]"
#disk_usage=`/bin/df / | /usr/bin/tail -1 | /bin/sed 's/^.* \([0-9]*\)%.*$/\1/'`

#slack_msg_head="${message_tag} ${host_name}"
#slack_msg_body="\`\`\`Disk usage ${disk_usage}%\`\`\`"
#slack_msg="\`${slack_msg_head}\`\n${slack_msg_body}"

#if [ $disk_usage -gt 90 ]; then
#    # mail notification
#    echo "Disk usage alert: $disk_usage %" | /usr/bin/mail -s "[WARNING][`hostname`] disk space alert" <target e-mail address>
#
#    # slack notification
#    curl -X POST -H 'Content-type: application/json' --data '{"text": "'"${slack_msg}"'"}' <slack webhook url>
#fi

# new one, this allows to specify which disk to watch
#!/bin/sh

HOST_NAME="your host, or maybe you can fetch from your local"
TARGET_PARTITION=/dev/sda
NOTE_THRESHOLD=95

SLACK_WEBHOOK_API_URL='https://hooks.slack.com/services/****'

# get used persent
USAGE_VAL=`df -h | grep $TARGET_PARTITION | awk '{ print $5 }' | sed -e '$s/.$//'`

if [ $USAGE_VAL -gt $NOTE_THRESHOLD ]
then
    #echo "Disk:$TARGET_PARTITION usage: $USAGE_VAL %" | /bin/mail -s "[ALERT][hostname] disk space alert" YOUR_EMAIL_ADDRESS
    JSON="{ \"text\": \"\`[ALERT][$HOST_NAME]\`\n\`\`\`Disk:$TARGET_PARTITION usage: $USAGE_VAL%\`\`\`\" }"
    RET=`curl -s -X POST -H 'Content-Type: application/json' -d "$JSON" $SLACK_WEBHOOK_API_URL`
fi