Convert a certificate into the cer,crt,der,pem format

For different reason we need the different format of certificates for different operating system, many of sites offering you to convert the certificates in different format online but if you have basic knowledge of command then you can do it by own by just typing simple commands

Firstly you need to installed the openssl on to your machine, see here how to install openssl for linux and centos.

Now moved to that folder in which your certificate have, use following commands as your need.

Convert x509 to PEM

openssl x509 -in cert.cer -outform PEM -out cert.pem

openssl x509 -in cert.crt -outform PEM -out cert.pem

Convert PEM to DER

openssl x509 -outform der -in cert.pem -out cert.der

Convert DER to PEM

openssl x509 -inform der -in cert.der -out cert.pem

Conver PEM to CER

openssl x509 -inform PEM -in cert.pem -outform DER -out cert.cer