Some useful RAC commands / utilities...

To start CRS :- 

/etc/init.d/init.crs start    
OR   
crsctl start crs


To check CRS services :-

$ORA_CRS_HOME/bin/crs_stat -t
$ORA_CRS_HOME/bin/crsctl check crs
$ORA_CRS_HOME/bin/crsctl check evmd
$ORA_CRS_HOME/bin/crsctl check cssd
$ORA_CRS_HOME/bin/crsctl check crsd


To stop CRS :- 

/etc/init.d/init.crs stop     
OR   
crsctl stop crs


To start database and all instances :-

srvctl start database -d <database> -o <options :- force, open, mount, nomount>


To Stop database and all instances :-

srvctl stop database -d <database> -o <options :- immediate, abort, normal, transactional>


To start / check status / stop services controlled by srvctl :-

srvctl [start|status|stop] database -d <database>
srvctl [start|status|stop] instance -d <database> -i <instance>,<instance>
srvctl [start|status|stop] service -d <database> -s <service>,<service> -i <instance>,<instance>
srvctl [start|status|stop] nodeapps -n <node>
srvctl [start|status|stop] asm -n <node>