curl -s domain.com/core/install.php | grep site-version | grep -oE "[0-9]+\.[0-9]+\.[0-9]+"
result is exact version, but must be also correct protocol - http or https
D7:
curl -s https://domain.com/CHANGELOG.txt |head -n5 |grep -oE "[0-9]+\.[0-9]+"
curl -s domain.com/core/install.php | grep site-version | grep -oE "[0-9]+\.[0-9]+\.[0-9]+"
result is exact version, but must be also correct protocol - http or https
D7:
curl -s https://domain.com/CHANGELOG.txt |head -n5 |grep -oE "[0-9]+\.[0-9]+"