Question

I want to setup a cron job to rsync a remote system to a backup partition, something like:

bash -c 'rsync -avz --delete --exclude=proc --exclude=sys root@remote1:/ /mnt/remote1/' 

I would like to be able to ‘set it and forget it’ but what if /mnt/remote1 becomes unmounted? (After a reboot or something) I’d like to error out if /mnt/remote1 isn’t mounted, rather than filling up the local filesystem.

Edit:
Here is what I came up with for a script, cleanup improvements appreciated (especially for the empty then … else, I couldn’t leave them empty or bash errors)

#!/bin/bash  DATA=data ERROR='0'  if cut -d' ' -f2 /proc/mounts | grep -q '^/mnt/$1\$'; then     ERROR=0 else     if mount /dev/vg/$1 /mnt/$1; then         ERROR=0     else         ERROR=$?         echo 'Can't backup $1, /mnt/$1 could not be mounted: $ERROR'     fi fi  if [ '$ERROR' = '0' ]; then     if cut -d' ' -f2 /proc/mounts | grep -q '^/mnt/$1/$DATA\$'; then         ERROR=0     else         if mount /dev/vg/$1$DATA /mnt/$1/data; then             ERROR=0         else             ERROR=$?             echo 'Can't backup $1, /mnt/$1/data could not be mounted.'         fi     fi fi  if [ '$ERROR' = '0' ]; then     rsync -aqz --delete --numeric-ids --exclude=proc --exclude=sys \         root@$1.domain:/ /mnt/$1/     RETVAL=$?     echo 'Backup of $1 completed, return value of rsync: $RETVAL' fi 

Answer 1

if cut -d' ' -f2 /proc/mounts | grep '^/mnt/remote1$' >/dev/null; then     rsync -avz ... fi 

Get the list of mounted partitions from /proc/mounts, only match /mnt/remote1 (and if it is mounted, send grep’s output to /dev/null), then run your rsync job.

Recent greps have a -q option that you can use instead of sending the output to /dev/null.