/usr/bin/php /var/www/html/katharismos/cli/joomla.php akeeba:backup:take
The system responds
Taking a backup with Akeeba Backup
==================================
Starting backup using profile #1.
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In FactoryStorage.php line 58:
Backup output directory /var/www/html/katharismos/administrator/components/com_akeebabackup/backup needs to be both readable and
writeable to PHP for this backup software to function correctly.
akeeba:backup:take [--profile[PROFILE]] [--description[DESCRIPTION]] [--comment[COMMENT]] [--overrides[OVERRIDES]] [-h|--help] [-q|--quiet] [-v|vv|vvv|--verbose] [-V|--version] [--ansi] [--no-ansi] [-n|--no-interaction] [--live-site[LIVE-SITE]] [--]
Manual backup from admin panel works just fine.