It is hard to find a command-line-based ftp client that support SSL/TLS.

Installation

FreeBSD

Enable the TLS by checking the box in the configure dialog

$ sudo portmaster ftp/lftp

Arch Linux

$ abs
$ mkdir ~/abs
$ cp -r /var/abs/lftp ~/abs
$ cd ~/abs/lftp

We need to modify the PKGBUILD of lftp

...
depends=('gcc-libs' 'readline' 'openssl' 'expat' 'sh')
...
build() {
    cd ${pkgname}-${pkgver}
    ./configure --prefix=/usr \
        --without-gnutls \
        --with-openssl \
        --without-included-regex \
        --disable-static
    make
}
...

Compile our patched source code of lftp. After that, install with the package which we built.

$ makepkg -s
$ sudo pacman -U lftp-4.5.5-1-x86_64.pkg.tar.xz

Mac OS X

First, update Homebrew formula by brew update. When it is done, just install it through brew install lftp.

Configuration

Just put a config file called .lftprc in your home directory. The content of the config file are listed below:

set ftp:ssl-force true
set ssl:verify-certificate off