crontab -e

# Start MySQL 8.0.23 with port 13306 on startup
@reboot cd ~/tmp/path-to-your-dir && cd mysql/versions/8.0.23 && dir=`pwd` && $dir/basedir/bin/mysqld --defaults-extra-file=$dir/datadir/mysql8-name1/my.cnf --daemonize --user=_dbdb_mysql --port=13306 --socket=/tmp/dbdb_mysql_13306.sock --basedir=$dir/basedir --plugin-dir=$dir/basedir/lib/plugin  --datadir=$dir/datadir/mysql8-name1 --log-error=$dir/datadir/mysql8-name1/mysqld.err --pid-file=$dir/datadir/mysql8-name1/mysql.pid

# Start MySQL 8.0.23 with port 23306 on startup
@reboot cd ~/tmp/path-to-your-dir && cd mysql/versions/8.0.23 && dir=`pwd` && $dir/basedir/bin/mysqld --defaults-extra-file=$dir/datadir/mysql8-name2/my.cnf --daemonize --user=_dbdb_mysql --port=23306 --socket=/tmp/dbdb_mysql_23306.sock --basedir=$dir/basedir --plugin-dir=$dir/basedir/lib/plugin --datadir=$dir/datadir/mysql8-name2 --log-error=$dir/datadir/mysql8-name2/mysqld.err --pid-file=$dir/datadir/mysql8-name2/mysql.pid

# Start MySQL 5.7.31 with port 33306 on startup
@reboot cd ~/tmp/path-to-your-dir && cd mysql/versions/5.7.31 && dir=`pwd` && $dir/basedir/bin/mysqld --defaults-extra-file=$dir/datadir/mysql5-name3/my.cnf --daemonize --user=_dbdb_mysql --port=33306 --socket=/tmp/dbdb_mysql_33306.sock --basedir=$dir/basedir --plugin-dir=$dir/basedir/lib/plugin  --datadir=$dir/datadir/mysql5-name3 --log-error=$dir/datadir/mysql5-name3/mysqld.err --pid-file=$dir/datadir/mysql5-name3/mysql.pid

# Start MySQL 5.7.31 with port 43306 on startup
@reboot cd ~/tmp/path-to-your-dir && cd mysql/versions/5.7.31 && dir=`pwd` && $dir/basedir/bin/mysqld --defaults-extra-file=$dir/datadir/mysql5-name4/my.cnf --daemonize --user=_dbdb_mysql --port=43306 --socket=/tmp/dbdb_mysql_43306.sock --basedir=$dir/basedir --plugin-dir=$dir/basedir/lib/plugin  --datadir=$dir/datadir/mysql5-name4 --log-error=$dir/datadir/mysql5-name4/mysqld.err --pid-file=$dir/datadir/mysql5-name4/mysql.pid