You can use procertm to convert digital certificates between .der and .pem file formats. To convert files from one file format to the other, use the following command line syntax:

Syntax

 procertm -c in_certout_cert
in_cert
The digital certificate whose file format you want to convert.
out_cert
The file format to which you want to convert the digital certificate.

The file utility performs the conversion based on the file-extension type. For example, if in_cert has a file extension type of .crt and out_cert has a file extension type of .pem, in_cert is converted from the .der to .pem format and written to the file out_cert.