Проблемы с использованием diff в bash для создания и проверки хэшей для службы Apache2

Question

Я получаю синтаксическую ошибку, используя diff в bash. Вот сценарий. часть в Bold - то, где у меня есть проблемы.

#!/bin/bash

FILES="/var/www/html/*";
varPath="/var/log/wwwHash";
tmpPath="/tmp/wwwHash";


if [[ -f $varPath ]];
        then mv $varPath $tmpPath;
fi

touch $varPath;


for f in $FILES ;
        do if [[ ! -d $f ]];
                then md5sum -t $f >> /var/log/wwwHash;
        fi ;
done;


if [[ `diff $varPath $tmpPath | wc -c` -lt 2 ]];
then echo "The files in the WWW/html folder have not changed";
else
        echo "The files in the WWW/html folder have changed."
        echo "The following are the files that have changed:"
        # Output which file has changed
        diff $varPath $tmpPath;
fi

В частности, эта часть вызывает синтаксическую ошибку.

if [[ `diff $varPath $tmpPath | wc -c` -lt 2 ]];
then echo "The files in the WWW/html folder have not changed";
else
        echo "The files in the WWW/html folder have changed."
        echo "The following are the files that have changed:"
        # Output which file has changed
        diff $varPath $tmpPath;
fi