Recently we faced with encoding problem with using mail linux utility.

Below is a part of simple script that is using for send report with using cron.

 if [ $err_f -ne 0 ]
   then
    echo "Backups directories $dirr_nn on rum-gpfsstorage0 were failed.
      See logs $log_nn  on rum-gpfs-b1.scanex.ru in /scripts/logs/ . Backups of other directories were successfull." | mail -r "backup-rum-gpfs@scanex.ru" -s "backup gpfs $dirr_nn directories failed" adm@scanex.ru
    else
    echo  "Backups all gpfs directories were successfull." |    mail -r "backup-rum-gpfs@scanex.ru" -s "backups all gpfs directories were successfull" adm@scanex.ru
    fi

When it started by cron all body text was unreadable. We looked at mail header:

 User-Agent: Heirloom mailx 12.4 7/29/08
 MIME-Version: 1.0
 Content-Type: application/octet-stream
 Content-Transfer-Encoding: 8bit

But when we started this script manualy all ware right. Mail header below:

 User-Agent: Heirloom mailx 12.4 7/29/08
 MIME-Version: 1.0
 Content-Type: text/plain; charset=utf-8
 Content-Transfer-Encoding: 8bit

To change content type to text/plain; charset=utf-8 we just add line to the begining of script:

export LANG=en_US.UTF-8