Read remaining data:

 USING: alien libc kernel-internals byte-arrays ;
 
 SYMBOL: buffer
 
 11 "uchar*" malloc-array buffer set
 
 "Hello world" buffer get string>memory
 
 buffer get 11 memory>string .
 
 "Hello world"
 
 11 [ buffer get swap alien-unsigned-1 ] each
 
 .s
 
 72
 101
 108
 108
 111
 32
 119
 111
 114
 108
 100 
 
 11 [ buffer get swap alien-unsigned-1 ] map
 
 >byte-array .
 
 { 72 101 108 108 111 32 119 111 114 108 100 }

Parse a file:

 openssl asn1parse -in file.pem

Parse a DER file:

 openssl asn1parse -inform DER -in file.der

Generate a PKCS#12 file:

 openssl pkcs12 -export -in certs.pem -out file.p12 -name "MY Certificate"

 The export option specifies that a PKCS#12 file will be generated (rather 
 than parsed).