mysql cmd login and \G vs \g

 mysql -u<username> -p<pwd> <dbName>

https://stackoverflow.com/questions/2277014/why-the-g-in-select-from-table-name-g

\g is same as ;

Short Answer
The ubiquitous semicolon command terminator ; is actually shorthand for the \g command, which is in itself shorthand for the go command. The go command is used both historically and currently in other flavours of SQL to submit batches of commands to be compiled and / or interpretted by the server. The \G command seems to inherit it's characteristic letter from \g, and is capitalised to further indicate a modified behaviour, as described by...
mysql> help ... \g go Send command to mysql server. \G ego Send command to mysql server, display result vertically. ...