# Build encryption command
my $gpg_command = "gpg --trust-model always -er 12345678 my_file.txt";

# Execute command and capture STDOUT.
my $gpg_results = `$gpg_command`;
print defined($gpg_results) ? $gpg_results : "Command failed\n";

# Save captured STDOUT to a file.
open( my $out, ">", "encrypted.pgp" ) or die "Could not open file for encrypted data - $!";