From Unix

The 'uniq' should not be necessary! 

ps -ef|grep [[o]]ra_pmon|sed -e 's/.*_//'|sort|uniq

From Windows

This shows the service name and its state 

sc query | perl -00 -ne 'print "$1 $2\
"  if /^SERVICE_NAME: OracleService(\\w+).TYPE.+?STATE\\s+:\\s+\\d\\s+(\\w+)/s'
DEV running

To see the value of ORACLE_HOME on Windows, use another sc query: 

sc qc OracleServiceDEV

The ORACLE_HOME and the instance name can be found on the 'BINARY_PATH_NAME' line. 

SERVICE_NAME: OracleServiceDEV
DISPLAY_NAME: Oracle Instance
        TYPE               : 10  WIN32_OWN_PROCESS
        START_TYPE         : 3   DEMAND_START
        ERROR_CONTROL      : 1   NORMAL
        BINARY_PATH_NAME   : c:\\oracle\\product\\11.2.0\\db\\bin\\ORACLE.EXE DEV
        LOAD_ORDER_GROUP   :
        TAG                : 0
        DISPLAY_NAME       : OracleServiceDEV
        DEPENDENCIES       :
        SERVICE_START_NAME : LocalSystem