需要srm：
./bash/profile:

function enc() {
  tar zcvf - $1 | openssl aes-256-cbc -salt -out $1.aes && srm -mfzr $1
}
function dec() {
  openssl aes-256-cbc -d -in $1.aes | tar zxvf - && rm -f $1.aes
}

参考：
https://github.com/JElchison/encrypt-tool/blob/master/encrypt-tool.sh
http://blog.extracheese.org/2010/05/the-tar-pipe.html
https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man1/srm.1.html
http://netsecurity.51cto.com/art/201301/378513.htm
http://www.361way.com/openssl-encrypt-file/2692.html