MySQL

Repair
mysqlcheck -r -u'база_данных' -p'пароль_базы_данных' 'база_данных' 
 REPAIR TABLE tablename USE_FRM; 
 Если побилась mysql.user и мускуль из-за этого не поднимается 
 for i in $(ls *.MYI | awk -F'.' '{print $1}') ; do myisamchk -r -q $i ;done

Проблемы с переносом баз
ERROR 1118 (42000): Row size too large (> 8126). Changing some columns to TEXT or BLOB may help. In current row format, BLOB prefix of 0 bytes is stored inline 
 sed -i 's#ENGINE=InnoDB#ENGINE=InnoDB ROW_FORMAT=DYNAMIC#g' dump.sql 
 ERROR 1416 (22003) at line 801: Cannot get geometry object from data you send to the GEOMETRY field 
 Где-то есть таблица с пустым геометрическим полем. Заполни его какими-нибудь координатами, 0,0,0 например 
 ERROR 1449 (HY000) at line 4012: The user specified as a definer ('asdf'@'localhost') does not exist 
 sed -i 's/\/\*!50013 DEFINER=`asdf`@`localhost` SQL SECURITY DEFINER \*\///g' dump.sql
 
 ERROR 1071 (42000) at line 874: Specified key was too long; max key length is 255 bytes 
 sed -i 's/tinytext/VARCHAR(255)/g'

SQL
SQL alter/convert 
 
 таблицу и поля в кодировки 
 
 ALTER TABLE `DATABASE`.`TABLE` CONVERT TO CHARACTER SET utf8 COLLATE utf8_unicode_ci; 
 
 базу, таблицы, поля в кодировки 
 
 ALTER DATABASE `DATABASE` DEFAULT CHARSET=utf8 COLLATE utf8_bin; 
 https://stackoverflow.com/questions/6115612/how-to-convert-an-entire-mysql-database-characterset-and-collation-to-utf-8#6115705 
 
 Use the ALTER DATABASE and ALTER TABLE commands. 
 ALTER DATABASE databasename CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
ALTER TABLE tablename CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci; 
 Or if you're still on MySQL 5.5.2 or older which didn't support 4-byte UTF-8, use utf8 instead of utf8mb4: 
 ALTER DATABASE databasename CHARACTER SET utf8 COLLATE utf8_unicode_ci;
ALTER TABLE tablename CONVERT TO CHARACTER SET utf8 COLLATE utf8_unicode_ci;

клиент
Красивый шелл: 
 prompt='\u at \h in \d> '