在Linux系統下安裝MySQL，有時候可能會出現沒有配置文件的情況。這時候我們需要手動創建并配置配置文件。

以下步驟是基于Ubuntu系統的安裝方法，請根據自己的系統進行對應操作。

1. 安裝MySQL
sudo apt-get install mysql-server
2. 檢查是否安裝成功
sudo service mysql status
3. 創建配置文件
sudo touch /etc/mysql/my.cnf
4. 使用編輯器打開my.cnf
sudo vi /etc/mysql/my.cnf
5. 將下列代碼粘貼至文件中 
[client]   
port            = 3306  
socket          = /var/run/mysqld/mysqld.sock
[mysqld_safe]  
socket          = /var/run/mysqld/mysqld.sock  
nice            = 0  
[mysqld]  
user            = mysql  
pid-file        = /var/run/mysqld/mysqld.pid  
socket          = /var/run/mysqld/mysqld.sock  
port            = 3306  
basedir         = /usr  
datadir         = /var/lib/mysql  
tmpdir          = /tmp  
skip-external-locking  
bind-address            = 127.0.0.1  
key_buffer              = 16M  
max_allowed_packet      = 16M  
thread_stack            = 192K  
thread_cache_size       = 8  
myisam-recover         = BACKUP  
query_cache_limit       = 1M  
query_cache_size        = 16M  
log_error = /var/log/mysql/error.log  
[mysqldump]  
quick  
quote-names  
max_allowed_packet      = 16M  
[mysql]  
#no-auto-rehash # faster start of mysql but no tab completition  
[isamchk]  
key_buffer              = 16M  
!includedir /etc/mysql/conf.d/
6. 保存文件并重啟MySQL服務
sudo service mysql restart

經過以上步驟，你就成功地創建了MySQL配置文件，并且完成了配置。接下來，你可以愉快地使用MySQL了！