LOGS :----->CRS, RDBMS, PDBS, ASM LOGS LOCATION ?

 That's all you need:

# Alert Logs

tail -n 1000 ${ORACLE_BASE}/diag/rdbms/<dbname>/<instance_name>/trace/alert_<instance_name>.log

# Listener Logs

tail -n 1000 ${ORACLE_BASE}/diag/tnslsnr/$(hostname)/listener/trace/listener.log

# Clusterware Logs

tail -n 1000 ${GRID_HOME}/log/$(hostname)/alert$(hostname).log

=> CRS: 

$ORACLE_BASE/diag/crs/$(hostname)/crs/trace/alert.log

=> ASM: 

$ORACLE_BASE/diag/+asm/<ASM_SID>/trace/alert_<ASM_SID>.log

=> RDBMS-Instances: $ORACLE_BASE/rdbms/<DB_NAME>/<DB_SID>/trace/alert_<DB_SID>.log

=> PDBs: There is not specific log for PDBS. Please see the alert.log of the corresponding RDBMS instances

 Locations of Oracle Clusterware Component Log Files

best :- ${GRID_HOME}/log/$(hostname)

Component	Log File LocationFoot 1
Cluster Ready Services Daemon (CRSD) Log Files	Grid_home/log/host_name/crsd
Cluster Synchronization Services (CSS)	Grid_home/log/host_name/cssd
Cluster Time Synchronization Service (CTSS)	Grid_home/log/host_name/ctssd
Grid Plug and Play	Grid_home/log/host_name/gpnpd
Multicast Domain Name Service Daemon (MDNSD)	Grid_home/log/host_name/mdnsd
Oracle Cluster Registry	Oracle Cluster Registry tools (OCRDUMP, OCRCHECK, OCRCONFIG) record log information in the following location: Grid_home/log/host_name/client Cluster Ready Services records Oracle Cluster Registry log information in the following location: Grid_home/log/host_name/crsd
Oracle Grid Naming Service (GNS)	Grid_home/log/host_name/gnsd
Oracle High Availability Services Daemon (OHASD)	Grid_home/log/host_name/ohasd
Event Manager (EVM) information generated by evmd	Grid_home/log/host_name/evmd
Oracle RAC RACG	The Oracle RAC high availability trace files are located in the following two locations: Grid_home/log/host_name/racg $ORACLE_HOME/log/host_name/racg Core files are in subdirectories of the log directory. Each RACG executable has a subdirectory assigned exclusively for that executable. The name of the RACG executable subdirectory is the same as the name of the executable. Additionally, you can find logging information for the VIP and database in these two locations, respectively.
Server Manager (SRVM)	Grid_home/log/host_name/srvm
Disk Monitor Daemon (diskmon)	Grid_home/log/host_name/diskmon
Grid Interprocess Communication Daemon (GIPCD)	Grid_home/log/host_name/gipcd