add check usage script

bin/check-disk-usage

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+
+USAGE=$(df / | awk 'NR!=1{print substr($5, 1, length($5)-1)}')
+ALERT=90
+
+if [ $USAGE -ge $ALERT ]; then
+  echo "Quedándose sin espacio de disco en \`$(hostname)\`: ${USAGE}%" | xargs -0 telegram-bot
+fi
+
+exit 0;

cron.d/INSTALL

@@ -4,6 +4,6 @@ source commons
 ensure_root && ensure_args $@
 
 filename=$(basename -s .sample $1)
-cat $1 | sed "s/\* \* \* \* \*/$2/" | sudo tee /etc/cron.d/$filename && sudo chmod 644 /etc/cron.d/$filename
+cat $1 | sed "s/\* \* \* \* \*/${2//\//\\/}/" | sudo tee /etc/cron.d/$filename && sudo chmod 644 /etc/cron.d/$filename
 
 exit 0

cron.d/check-disk-usage.sample

@@ -0,0 +1,3 @@
+PATH=/usr/bin:/bin:/usr/local/bin:/usr/local/sbin:/usr/sbin:/sbin
+DEBIAN_FRONTEND=noninteractive
+* * * * *      root    check-disk-usage

cron.d/check-external-drive.sample

@@ -1,4 +1,3 @@
 PATH=/usr/bin:/bin:/usr/local/bin:/usr/local/sbin:/usr/sbin:/sbin
 DEBIAN_FRONTEND=noninteractive
 * * * * *      root    check-external-drive
-