一、设置自动登录图形化操作界面

/etc/gdm/custom.conf
修改内容：

AutomaticLoginEnable=true
AutomaticLogin=root

# GDM configuration storage

[daemon]
AutomaticLoginEnable=true
AutomaticLogin=root

[security]

[xdmcp]

[chooser]

[debug]
# Uncomment the line below to turn on debugging
#Enable=true

二、CentOS7设置网卡开机启动

/etc/sysconfig/network-scripts/ifcfg-ens*
修改内容：

ONBOOT=yes

TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=dhcp
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=ens33
UUID=e45d27e9-3a33-4519-9017-ea203a722571
DEVICE=ens33
ONBOOT=yes

使生效：

systemctl restart network

三、修改系统语言编码

/etc/sysconfig/i18n
修改内容：

LANG="en_US.UTF-8"
LANG="zh_CN.UTF-8"

LANG="en_US.UTF-8"
SYSFONT="latarcyrheb-sun16"

使生效：

source /etc/sysconfig/i18n

四、设置登录系统后提示信息

/etc/motd
修改内容：

Hello world!

Hello world!

五、永久修改命令提示符

/etc/profile.d/env.sh

默认不存在，需要手工创建。
该文件还可以写入其他命令的环境变量参数。

修改内容：

PS1="[\e[1;32m][\u@\h \w]\$[\e[0m]"

PS1="\[\e[1;32m\][\u@\h \w]\\$\[\e[0m\]"

六、永久定义命令别名

/home/USERNAME/.bashrc
/etc/bashrc
修改内容：

alias rm='rm -i'
alias cp='cp -i --backup=numbered'
alias mv='mv -i'
alias cdnet='cd /etc/sysconfig/network-scripts/'
alias rm='mv -t /recycle/'

# .bashrc

# User specific aliases and functions

alias rm='rm -i'
alias cp='cp -i --backup=numbered'
alias mv='mv -i'
alias cdnet='cd /etc/sysconfig/network-scripts/'
alias rm='mv -t /recycle/'

# Source global definitions
if [ -f /etc/bashrc ]; then
        . /etc/bashrc
fi

使生效：

source .bashrc

七、修改命令行历史最多存储数

/etc/profile
修改内容：

HISTSIZE=1000

# /etc/profile

# System wide environment and startup programs, for login setup
# Functions and aliases go in /etc/bashrc

# It's NOT a good idea to change this file unless you know what you
# are doing. It's much better to create a custom.sh shell script in
# /etc/profile.d/ to make custom changes to your environment, as this
# will prevent the need for merging in future updates.

pathmunge () {
    case ":${PATH}:" in
        *:"$1":*)
            ;;
        *)
            if [ "$2" = "after" ] ; then
                PATH=$PATH:$1
            else
                PATH=$1:$PATH
            fi
    esac
}


if [ -x /usr/bin/id ]; then
    if [ -z "$EUID" ]; then
        # ksh workaround
        EUID=`/usr/bin/id -u`
        UID=`/usr/bin/id -ru`
    fi
    USER="`/usr/bin/id -un`"
    LOGNAME=$USER
    MAIL="/var/spool/mail/$USER"
fi

# Path manipulation
if [ "$EUID" = "0" ]; then
    pathmunge /usr/sbin
    pathmunge /usr/local/sbin
else
    pathmunge /usr/local/sbin after
    pathmunge /usr/sbin after
fi

HOSTNAME=`/usr/bin/hostname 2>/dev/null`
HISTSIZE=1000
if [ "$HISTCONTROL" = "ignorespace" ] ; then
    export HISTCONTROL=ignoreboth
else
    export HISTCONTROL=ignoredups
fi

export PATH USER LOGNAME MAIL HOSTNAME HISTSIZE HISTCONTROL

# By default, we want umask to get set. This sets it for login shell
# Current threshold for system reserved uid/gids is 200
# You could check uidgid reservation validity in
# /usr/share/doc/setup-*/uidgid file
if [ $UID -gt 199 ] && [ "`/usr/bin/id -gn`" = "`/usr/bin/id -un`" ]; then
    umask 002
else
    umask 022
fi

for i in /etc/profile.d/*.sh ; do
    if [ -r "$i" ]; then
        if [ "${-#*i}" != "$-" ]; then
            . "$i"
        else
            . "$i" >/dev/null
        fi
    fi
done

unset i
unset -f pathmunge

八、设置登录系统前提示信息

/etc/issue
修改内容：

Hostname is /n

CentOS release 6.9 (Final)
Kernel \r on an \m

Hostname is \n

九、修改用户相关设置

用户邮件文件路径、密码最长有效期、密码最短有效期、密码长度、密码警告期、普通用户ID起始、普通用户ID结束、系统用户ID起始、系统用户ID结束、组ID起始、组ID结束、默认创建家目录、密码加密算法

/etc/login.defs
修改内容：

MAIL_DIR /var/spool/mail
PASS_MAX_DAYS 99999
PASS_MIN_DAYS 0
PASS_MIN_LEN 5
PASS_WARN_AGE 7
GID_MIN 1000
GID_MAX 60000
SYS_UID_MIN 201
SYS_UID_MAX 999
GID_MIN 1000
GID_MAX 60000
CREATE_HOME yes
ENCRYPT_METHOD SHA512

#
# Please note that the parameters in this configuration file control the
# behavior of the tools from the shadow-utils component. None of these
# tools uses the PAM mechanism, and the utilities that use PAM (such as the
# passwd command) should therefore be configured elsewhere. Refer to
# /etc/pam.d/system-auth for more information.
#

# *REQUIRED*
#   Directory where mailboxes reside, _or_ name of file, relative to the
#   home directory.  If you _do_ define both, MAIL_DIR takes precedence.
#   QMAIL_DIR is for Qmail
#
#QMAIL_DIR      Maildir
MAIL_DIR        /var/spool/mail
#MAIL_FILE      .mail

# Password aging controls:
#
#       PASS_MAX_DAYS   Maximum number of days a password may be used.
#       PASS_MIN_DAYS   Minimum number of days allowed between password changes.
#       PASS_MIN_LEN    Minimum acceptable password length.
#       PASS_WARN_AGE   Number of days warning given before a password expires.
#
PASS_MAX_DAYS   99999
PASS_MIN_DAYS   0
PASS_MIN_LEN    5
PASS_WARN_AGE   7

#
# Min/max values for automatic uid selection in useradd
#
UID_MIN                  1000
UID_MAX                 60000
# System accounts
SYS_UID_MIN               201
SYS_UID_MAX               999

#
# Min/max values for automatic gid selection in groupadd
#
GID_MIN                  1000
GID_MAX                 60000
# System accounts
SYS_GID_MIN               201
SYS_GID_MAX               999

#
# If defined, this command is run when removing a user.
# It should remove any at/cron/print jobs etc. owned by
# the user to be removed (passed as the first argument).
#
#USERDEL_CMD    /usr/sbin/userdel_local

#
# If useradd should create home directories for users by default
# On RH systems, we do. This option is overridden with the -m flag on
# useradd command line.
#
CREATE_HOME     yes

# The permission mask is initialized to this value. If not specified,
# the permission mask will be initialized to 022.
UMASK           077

# This enables userdel to remove user groups if no members exist.
#
USERGROUPS_ENAB yes

# Use SHA512 to encrypt password.
ENCRYPT_METHOD SHA512

十、新用户默认设置

用户默认属于的主组、密码宽限期、用户有效期、新建用户shell类型、新建用户家目录模板目录

/etc/default/useradd
修改内容：

GROUP=100
INACTIVE=-1
EXPIRE=
SHELL=/bin/bash
SKEL=/etc/skel

# useradd defaults file
GROUP=100
HOME=/home
INACTIVE=-1
EXPIRE=
SHELL=/bin/bash
SKEL=/etc/skel
CREATE_MAIL_SPOOL=yes

十一、永久修改文件默认权限

/home/USERNAME/.bashrc
/etc/bashrc
修改内容：

umask 251

# .bashrc

# User specific aliases and functions

alias rm='rm -i'
alias cp='cp -i --backup=numbered'
alias mv='mv -i'
alias cdnet='cd /etc/sysconfig/network-scripts/'
alias rm='mv -t /recycle/'

# Source global definitions
if [ -f /etc/bashrc ]; then
        . /etc/bashrc
fi

umask 251

使生效：

source .bashrc

十二、vim配置文件

设置编辑.sh后缀的文件时忽略大小写、光标线、自动缩进，自动填写作者名、QQ号、日期、文件名、链接、备注、版权。

/USERNAME/.vimrc
修改内容：

set ignorecase
set cursorline
set autoindent
autocmd BufNewFile *.sh exec ":call SetTitle()"
func SetTitle()
if expand("%:e") == 'sh'
call setline(1,"#!/bin/bash")
call setline(2,"#")
call setline(3,"#********************************************************************")
call setline(4,"#Author: KKK")
call setline(5,"#QQ: 123456789")
call setline(6,"#Date: ".strftime("%Y-%m-%d"))
call setline(7,"#FileName： ".expand("%"))
call setline(8,"#URL: http://www.kkk.com")
call setline(9,"#Description： The test script")
call setline(10,"#Copyright (C): ".strftime("%Y")." All rights reserved")
call setline(11,"#********************************************************************")
call setline(12,"")
endif
endfunc
autocmd BufNewFile * normal G

set ignorecase
set cursorline
set autoindent
autocmd BufNewFile *.sh exec ":call SetTitle()"
func SetTitle()
        if expand("%:e") == 'sh'
        call setline(1,"#!/bin/bash")
        call setline(2,"#")
        call setline(3,"#********************************************************************")
        call setline(4,"#Author:                KKK")
        call setline(5,"#QQ:                    123456789")
        call setline(6,"#Date:                  ".strftime("%Y-%m-%d"))
        call setline(7,"#FileName：             ".expand("%"))
        call setline(8,"#URL:                   http://www.kkk.com")
        call setline(9,"#Description：          The test script")
        call setline(10,"#Copyright (C):        ".strftime("%Y")." All rights reserved")
        call setline(11,"#********************************************************************")
        call setline(12,"")
        endif
endfunc
autocmd BufNewFile * normal G