/usr/bin/berkeley_db42_svc
/usr/bin/db42_archive
/usr/bin/db42_checkpoint
/usr/bin/db42_deadlock
/usr/bin/db42_dump
/usr/bin/db42_load
/usr/bin/db42_printlog
/usr/bin/db42_recover
/usr/bin/db42_stat
/usr/bin/db42_upgrade
/usr/bin/db42_verify
You may install this package on CentOS with
yum
install compat-db42