Usie this command to encrypt and decrypt a file using PGP in linux.

gpg -c file
gpg -o file -d file.gpg (output to file)

Works on OS X, Linux, anywhere with OpenSSL installed:

To encrypt a file:

openssl des3 -salt -in infile.txt -out encryptedfile.txt

To decrypt the file:

openssl des3 -d -salt -in encryptedfile.txt -out normalfile.txt

Encrypt/Decrypt a file with GNU Privacy Guard - GPG.

#Encrypt
gpg -c file

#Decrypt
gpg file.gpg