Apache error log location on Debian,ubuntu or Linux Mint
Default error log
On Debian-based Linux, the system-wide Apache error log default location is /var/log/apache2/error.log. The default location can be modified by editing the Apache configuration file.
Custom error logs
To find a custom error log location, open/etc/apache2/apache2.conf with a text editor and look for a line that begins with errorlog, which specifies the location of the custom Apache error log file. For example, the following lines can be found in an unmodified Apache configuration file:
ErrorLog ${APACHE_LOG_DIR}/error.log
In this case, the location is configured with the APACHELOGDIR environment variable, which is already defined in/etc/apache2/envvars.
export APACHE_LOG_DIR=/var/log/apache2$SUFFIX
In reality, errorlog may point to any path in your Linux system
Location of the Ubuntu system Apache log files