emerge --config =dev-db/mariadb-5.5.23
 
 
Configuring pkg...
 
 * Please provide a password for the mysql 'root' user now, in the
 * MYSQL_ROOT_PASSWORD env var or through the /root/.my.cnf file.
 * Avoid ["'\_%] characters in the password
    >
 * Retype the password
    >
 * ERROR: dev-db/mariadb-5.5.23 failed (config phase):
 *   Failed to run mysql_install_db. Please review /var/log/mysql/mysqld.err AND /var/tmp/portage/dev-db/mariadb-5.5.23/temp/mysql_install_db.log
 *  
 * Call stack:
 *     ebuild.sh, line   85:  Called pkg_config
 *   environment, line 3249:  Called mysql-v2_pkg_config
 *   environment, line 2903:  Called die
 * The specific snippet of code:
 *           die "Failed to run mysql_install_db. Please review ${EPREFIX}/var/log/mysql/mysqld.err AND ${TMPDIR}/mysql_install_db.log";
 *  
 * If you need support, post the output of `emerge --info '=dev-db/mariadb-5.5.23'`,
 * the complete build log and the output of `emerge -pqv '=dev-db/mariadb-5.5.23'`.
 * This ebuild is from an overlay named 'gentoo': '/var/db/pkg/'
 * The complete build log is located at '/var/tmp/portage/dev-db/mariadb-5.5.23/temp/build.log'.
 * The ebuild environment file is located at '/var/tmp/portage/dev-db/mariadb-5.5.23/temp/environment'.
 * Working directory: '/var/tmp/portage/dev-db/mariadb-5.5.23/temp'
 * S: '/var/tmp/portage/dev-db/mariadb-5.5.23/work/mariadb-5.5.23'

whereis mysql_install_db
mysql_install_db: /usr/share/man/man1/mysql_install_db.1.bz2