切换root用户模式 (已在root模式下的请忽略)
sudo -i
然后提示你输入当前用户密码，输入密码后回车后如果密码正确控制台就变成root@***:/#了。
更新软件源且安装vsftp
sudo apt-get update
apt-get install vsftpd
创建工作目录
为了操作方便管理，我们给FTP创建自定义FTP目录和用户组,创建FTP目录?/home/ftp 当然你也可以创建到其它目录
mkdir /home/ftp
创建FTP用户组 ftp-g??这个你们也可以用其它组名
groupadd ftp-g
设置FTP目录读写权限(注：用户登陆的根目录如果权限设置的太大会导致无法登陆，根目录下的子目录可以给很大的权限，一般服务器都是采用755权限
chmod 755 /home/ftp
设置文件夹归属 root 以及 我们新建的 FTP用户组
chown root:ftp-g /home/ftp
到此，ftp的根目录就已经创建完成了
设置FTP用户目录以及添加FTP用户
为用户ftp_pub 创建目录 pub并设置权限
mkdir /home/ftp/pub
chmod 755 /home/ftp/pub
添加用户 ftp_pub 并设置归属用户组为 ftp-g 以及设置缺省目录(FTP登陆目录) -s /sbin/nologin 禁止用户登陆控制台
useradd -g ftp-g -d /home/ftp/pub -s /sbin/nologin ftp_pub
给新用户ftp_pub设置密码(无密码不能登陆，然后按照提示输入两遍密码，比如我们设置为 123456798
passwd ftp_pub
更改目录归属,ftp下新建的这个目录只有ftp_pub才能够被更改
chown ftp_pub:ftp-g?/home/ftp/pub
增加上传目录不可删除功能，在配置文件中增加user_config_dir=/etc/vsftpd_user_ctrl，同时在vsftpd_user_ctrl文件夹中增加对应的账户名字的文件，目的就是对指定的账户进行操作限制
增加的指令,cmds_denied=DELE，就是防止删除操作，同样的指令操作还有很多，可以到网络上面自行百度。到此，就实现了普通用户的操作限制，比如限制指定用户删除操作
给FTP开放外网端口(默认:tcp端口 21)
ufw allow 21/tcp
启动FTP服务
/etc/init.d/vsftpd start
总结
普通用户还是比较好搭建服务器，关键是管理员权限不好控制，看来是需要更加复杂的控制才行，需要通过单独的文件进行控制，比如用vsftp的用户控制或者用用户的权限控制，比如登陆以后给与某个用户超级，最后还是解决了超级管理员的问题，在星期四晚上的最后一刻，还是解决了超级管理员的问题，就是设置root可以登录，同时登陆root账户，那么所有的文件权限也都有了
下面的代码是是vsftpd的配置文件配置对照表，严格按照下图对配置文件进行修改：
# Example config file /etc/vsftpd.conf
#
# The default compiled in settings are fairly paranoid. This sample file
# loosens things up a bit, to make the ftp daemon more usable.
# Please see vsftpd.conf.5 for all compiled in defaults.
#
# READ THIS: This example file is NOT an exhaustive list of vsftpd options.
# Please read the vsftpd.conf.5 manual page to get a full idea of vsftpd‘s
# capabilities.
#
#
# Run standalone???vsftpd can run either from an inetd or as a standalone
# daemon started from an initscript.
listen=YES
#
# This directive enables listening on IPv6 sockets. By default, listening
# on the IPv6 "any" address (::) will accept connections from both IPv6
# and IPv4 clients. It is not necessary to listen on *both* IPv4 and IPv6
# sockets. If you want that (perhaps because you want to listen on specific
# addresses) then you must run two copies of vsftpd with two configuration
# files.
listen_ipv6=NO
#
# Allow anonymous FTP? (Disabled by default).
anonymous_enable=NO
#
# Uncomment this to allow local users to log in.
local_enable=YES
#
# Uncomment this to enable any form of FTP write command.
write_enable=YES
#
# Default umask for local users is 077. You may wish to change this to 022,
# if your users expect that (022 is used by most other ftpd‘s)
local_umask=022
Uncomment this to allow the anonymous FTP user to upload files. This only
# has an effect if the above global write enable is activated. Also, you will
# obviously need to create a directory writable by the FTP user.
#anon_upload_enable=YES
#
# Uncomment this if you want the anonymous FTP user to be able to create
# new directories.
#anon_mkdir_write_enable=YES
#
# Activate directory messages - messages given to remote users when they
# go into a certain directory.
dirmessage_enable=YES
#
# If enabled, vsftpd will display directory listings with the time
# in??your??local??time??zone.??The default is to display GMT. The
# times returned by the MDTM FTP command are also affected by this
# option.
use_localtime=YES
#
# Activate logging of uploads/downloads.
xferlog_enable=YES
#
# Make sure PORT transfer connections originate from port 20 (ftp-data).
connect_from_port_20=YES
#
# If you want, you can arrange for uploaded anonymous files to be owned by
# a different user. Note! Using "root" for uploaded files is not
# recommended!
chown_uploads=YES
chown_username=root
#
# You may override where the log file goes if you like. The default is shown
# below.
xferlog_file=/var/log/vsftpd.log
#
# If you want, you can have your log file in standard ftpd xferlog format.
chown_uploads=YES
chown_username=root
#
# You may override where the log file goes if you like. The default is shown
# below.
xferlog_file=/var/log/vsftpd.log
#
# If you want, you can have your log file in standard ftpd xferlog format.
# Note that the default log file location is /var/log/xferlog in this case.
xferlog_std_format=YES
#
# You may change the default value for timing out an idle session.
#idle_session_timeout=600
#
# You may change the default value for timing out a data connection.
#data_connection_timeout=120
#
# It is recommended that you define on your system a unique user which the
# ftp server can use as a totally isolated and unprivileged user.
#nopriv_user=ftpsecure
#
# Enable this and the server will recognise asynchronous ABOR requests. Not
# recommended for security (the code is non-trivial). Not enabling it,
# however, may confuse older FTP clients.
#async_abor_enable=YES
#
# By default the server will pretend to allow ASCII mode but in fact ignore
# the request. Turn on the below options to have the server actually do ASCII
# mangling on files when in ASCII mode.
# Beware that on some FTP servers, ASCII support allows a denial of service
# attack (DoS) via the command "SIZE /big/file" in ASCII mode. vsftpd
# predicted this attack and has always been safe, reporting the size of the
# raw file.
# ASCII mangling is a horrible feature of the protocol.
#ascii_upload_enable=YES
# You may fully customise the login banner string:
ftpd_banner=Welcome to blah FTP service.
#
# You may specify a file of disallowed anonymous e-mail addresses. Apparently
# useful for combatting certain DoS attacks.
#deny_email_enable=YES
# (default follows)
#banned_email_file=/etc/vsftpd.banned_emails
#
# You may restrict local users to their home directories.??See the FAQ for
# the possible risks in this before using chroot_local_user or
# chroot_list_enable below.
#chroot_local_user=YES
#
# You may specify an explicit list of local users to chroot() to their home
# directory. If chroot_local_user is YES, then this list becomes a list of
# users to NOT chroot().
# (Warning! chroot‘ing can be very dangerous. If using chroot, make sure that
# the user does not have write access to the top level directory within the
# chroot)
#chroot_local_user=YES
#chroot_list_enable=YES
# (default follows)
#chroot_list_file=/etc/vsftpd.chroot_list
#
# You may activate the "-R" option to the builtin ls. This is disabled by
# default to avoid remote users being able to cause excessive I/O on large
# sites. However, some broken FTP clients such as "ncftp" and "mirror" assume
# the presence of the "-R" option, so there is a strong case for enabling it.
#ls_recurse_enable=YES
#
# Customization
#
# Some of vsftpd‘s settings don‘t fit the filesystem layout by
This option should be the name of a directory which is empty.??Also, the
# directory should not be writable by the ftp user. This directory is used
# as a secure chroot() jail at times vsftpd does not require filesystem
# access.
secure_chroot_dir=/var/run/vsftpd/empty
#
# This string is the name of the PAM service vsftpd will use.
pam_service_name=ftp
#
# This option specifies the location of the RSA certificate to use for SSL
# encrypted connections.
rsa_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
rsa_private_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
ssl_enable=NO
#
# Uncomment this to indicate that vsftpd use a utf8 filesystem.
utf8_filesystem=YES
user_config_dir=/etc/vsftpd_user_ctrl