MySQL Binary Installation (mysql_install_db) While installing from binaries. The below always gives error when we execute from 'scripts' directory

[mysql@hostname ~]$ cd /mysql/product/5.6.12/scripts/
[mysql@hostname ~]$ . mysql_install_db --defaults-file=my.cnf


-bash: use: command not found

But the same works fine when I execute one step back from scripts directory

[mysql@hostname ~]$ scripts/mysql_install_db --defaults-file=my.cnf


Question: Why this happens ?
I think you have a mistake, you can't execute:

[mysql@hostname ~]$ . mysql_install_db --defaults-file=my.cnf


Because the correct line is:

[mysql@hostname ~]$ ./mysql_install_db --defaults-file=my.cnf


You don't have in PATH environtment variable the current directory ".".