Add an SFTP-only user. Note: needs sshd_config to define the www-users group as sftp-only.

user.sh

#!/bin/bash
#-----------------------------------------------------------------------
# Add User Script
#-----------------------------------------------------------------------

# Create directory
mkdir -p /var/www/$1

# Add account
useradd -s/bin/sh -b/var/www -gwww-users $1

# Set Password
passwd $1

# Set public key
mkdir -p /var/www/$1/.ssh
chown $1 /var/www/$1/.ssh
chmod 700 /var/www/$1/.ssh

su -c "cd /var/www/$1/.ssh ; curl http://files.alexblackie.com/id_rsa.pub >> authorized_keys" $1

# Set up webroots
mkdir /var/www/$1/public
mkdir /var/www/$1/private

chown $1:www-data /var/www/$1/public
chown $1 /var/www/$1/private
chmod 740 /var/www/$1/private