Question

I am trying to sync a bunch of domains (a.com, b.com, and c.com) on a bunch of load balanced web nodes (w1, w2, w3).

I plan to build to node 1 (w1) and then rsync to the others with something like this:

rsync -arv /var/www/vhosts/a.com/ root@w1:/var/www/vhosts/a.com/

With a dynamic script like (assume I’m on w1 already) :

#!/bin/bash

DOMAINS="a.com b.com c.com"
NODES="w2 w3"

for DOMAIN in $DOMAINS; do
        for NODE in $NODES; do
                COMMAND="rsync -arv --exclude 'logs' --exclude '.git' /var/www/vhosts/$DOMAIN/ root@$NODE:/var/www/vhosts/$DOMAIN/"
                echo "$COMMAND"
                "$COMMAND"
        done
done

The first, manual, rsync works just fine. But for some reason my batch rsync script is breaking.

Anyone care to help debug for me? Thanks.

Answer 1

You have some excessive quoting going on there. Change this line:

"$COMMAND"

To this:

$COMMAND

When you put quotes around the whole thing, the shell interprets it as a single “token”. Here’s a simple example:

$ COMMAND="echo hello"
$ "$COMMAND"
bash: echo: command not found...
$ $COMMAND
hello