Deleting  alert log files, Trace Files Automated in Oracle Database

[oracle@localhost ~]$ adrci

ADRCI: Release 12.1.0.2.0 - Production on Tue Mar 7 10:42:16 2018

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ADR base = "/u01/app/grid"
adrci> show homes
ADR Homes:
diag/rdbms/_mgmtdb/-MGMTDB
diag/asm/+asm/+ASM2
diag/clients/user_root/host_1450230238_82
diag/clients/user_grid/host_1450230238_82
diag/crs/node2/crs
diag/tnslsnr/node2/mgmtlsnr
diag/tnslsnr/node2/listener
diag/tnslsnr/node2/listener_scan1
adrci> show h