ralph@firenze:~$ strace -eopen openssl verify -CAfile cas.crt ohdear.crt
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
open("/lib/x86_64-linux-gnu/libssl.so.1.0.0", O_RDONLY|O_CLOEXEC) = 3
open("/lib/x86_64-linux-gnu/libcrypto.so.1.0.0", O_RDONLY|O_CLOEXEC) = 3
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
open("/lib/x86_64-linux-gnu/libdl.so.2", O_RDONLY|O_CLOEXEC) = 3
open("/lib/x86_64-linux-gnu/libz.so.1", O_RDONLY|O_CLOEXEC) = 3
open("/usr/lib/ssl/openssl.cnf", O_RDONLY) = 3
open("/proc/meminfo", O_RDONLY|O_CLOEXEC) = 3
open("cas.crt", O_RDONLY)               = 3
open("ohdear.crt", O_RDONLY)            = 3
open("/usr/lib/ssl/certs/578d5c04.0", O_RDONLY) = 3
open("/etc/localtime", O_RDONLY|O_CLOEXEC) = 3
ohdear.crt: OK