title: mysqldump exclude tables does not exclude tables when using in a variable
body: <p>I am sure this is a simple one but struggling to understand the problem..</p>
  <p>I am pulling table names from a file</p>
  <pre><code># cat db.tbl.exclude
  wp_users
  wp_usermeta
  </code></pre>
  <p>and then creating a variable.</p>
  <pre><code>EXCLUDETABLE=$(while read -r tbl ; do echo --ignore-table=dbname.$tbl ; done &lt; db.tbl.exclude | sed -e :a -e '$!N; s/\n/ /; ta')
  </code></pre>
  <p>Example output:</p>
  <pre><code># echo $EXCLUDETABLE
  --ignore-table=dbname.wp_users --ignore-table=dbname.wp_usermeta
  </code></pre>
  <p>Now if I run mysqldump...</p>
  <pre><code>mysqldump -f --routines --events --single-transaction --extended-insert &quot;${EXCLUDETABLE}&quot; dbname&gt; dbname.sql
  </code></pre>
  <p>The tables exist in the database backup...</p>
  <p>just to ensure the command does actually work, I used the exact output of ${EXCLUDETABLE} and tested it.</p>
  <pre><code>mysqldump -f --routines --events --single-transaction --extended-insert --ignore-table=dbname.wp_users --ignore-table=dbname.wp_usermeta dbname &gt; dbname.sql
  </code></pre>
  <p>The tables exclude without issue.  Why is it problematic using a variable for these options?</p>