> mysql -uroot

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock' (61)

this means that the mysql server has not started: it is the daemon which initialise the socket,so at first run 

"mysql.server start", then mysql -uroot

a) mysql.server start (should return success)

b)mysql -uroot (return the mysql prompt)

c) exit

d) mysql.server stop (should return success)