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使用ImageMagick处理图片

命令格式
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convert -auto-orient -strip -compress JPEG2000 -quality 50 -resize 50% 1.jpg 2.jpg
参数说明
  1. -auto-orient

adjusts an image so that its orientation is suitable for viewing (i.e. top-left orientation).

根据图片旋转方向自动扶正

  1. -strip

strip the image of any profiles, comments or these PNG chunks: bKGD,cHRM,EXIF,gAMA,iCCP,iTXt,sRGB,tEXt,zCCP,zTXt,date.

清除图片档案信息，如EXIF

  1. -compress

Use pixel compression specified by type when writing the image.

Choices are:None,BZip,Fax,Group4,JPEG,JPEG2000,Lossless,LZW,RLEorZip.

指定图片压缩格式

  1. -quality

JPEG/MIFF/PNG compression level.

图片压缩质量，数值越高越清晰

  1. -resize

Resize an image.

改变图片尺寸

size General description (actual behavior can vary for different options and settings)
scale% Height and width both scaled by specified percentage.
宽高等比例缩放
scale-x%xscale-y% Height and width individually scaled by specified percentages. (Only one % symbol needed.)
分别指定缩放比例宽高
width Width given, height automagically selected to preserve aspect ratio.
xheight Height given, width automagically selected to preserve aspect ratio.
widthxheight Maximum values of height and width given, aspect ratio preserved.
widthxheight^ Minimum values of width and height given, aspect ratio preserved.
widthxheight! Width and height emphatically given, original aspect ratio ignored.
widthxheight> Shrinks an image with dimension(s) larger than the corresponding width and/or height argument(s).
widthxheight< Enlarges an image with dimension(s) smaller than the corresponding width and/or height argument(s).
area@ Resize image to have specified area in pixels. Aspect ratio is preserved.
x:y Here x and y denotes an aspect ratio (e.g. 3:2 = 1.5).
{size}{offset} Specifying the offset (default is +0+0). Below, {size} refers to any of the forms above.
{size}{+-}x{+-}y Horizontal and vertical offsets x and y, specified in pixels. Signs are required for both. Offsets are affected by ‑gravity setting. Offsets are not affected by % or other size operators.

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定义和用法

DATE_FORMAT() 函数用于以不同的格式显示日期/时间数据。

语法

DATE_FORMAT(date,format)
date 参数是合法的日期。 format 规定日期/时间的输出格式。
可以使用的格式有：

格式 描述
%a 缩写星期名
%b 缩写月名
%c 月，数值
%D 带有英文前缀的月中的天
%d 月的天，数值(00-31)
%e 月的天，数值(0-31)
%f 微秒
%H 小时 (00-23)
%h 小时 (01-12)
%I 小时 (01-12)
%i 分钟，数值(00-59)
%j 年的天 (001-366)
%k 小时 (0-23)
%l 小时 (1-12)
%M 月名
%m 月，数值(00-12)
%p AM 或 PM
%r 时间，12-小时（hh:mm:ss AM 或 PM）
%S 秒(00-59)
%s 秒(00-59)
%T 时间, 24-小时 (hh:mm:ss)
%U 周 (00-53) 星期日是一周的第一天
%u 周 (00-53) 星期一是一周的第一天
%V 周 (01-53) 星期日是一周的第一天，与 %X 使用
%v 周 (01-53) 星期一是一周的第一天，与 %x 使用
%W 星期名
%w 周的天 （0=星期日, 6=星期六）
%X 年，其中的星期日是周的第一天，4 位，与 %V 使用
%x 年，其中的星期一是周的第一天，4 位，与 %v 使用
%Y 年，4 位
%y 年，2 位

实例

下面的脚本使用 DATE_FORMAT() 函数来显示不同的格式。我们使用 NOW() 来获得当前的日期/时间：

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DATE_FORMAT(NOW(),'%b %d %Y %h:%i %p')
DATE_FORMAT(NOW(),'%m-%d-%Y')
DATE_FORMAT(NOW(),'%d %b %y')
DATE_FORMAT(NOW(),'%d %b %Y %T:%f')

结果如下所示：

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Nov 04 2008 11:45 PM
11-04-2008
04 Nov 08
04 Nov 2008 11:45:34:243

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Node.js® is a JavaScript runtime built on Chrome’s V8 JavaScript engine. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient. Node.js’ package ecosystem, npm, is the largest ecosystem of open source libraries in the world.

Installing Node.js via package manager

Note: The packages on this page are maintained and supported by their respective packagers, not the Node.js core team. Please report any issues you encounter to the package maintainer. If it turns out your issue is a bug in Node.js itself, the maintainer will report the issue upstream.

Arch Linux

Node.js and npm packages are available in the Community Repository.

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pacman -S nodejs npm

Debian and Ubuntu based Linux distributions

Also including: Linux Mint, Linux Mint Debian Edition (LMDE), elementaryOS, bash on Windows and others.

NOTE: If you are using Ubuntu Precise or Debian Wheezy, you might want to read about running Node.js >= 6.x on older distros.

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curl -sL https://deb.nodesource.com/setup_6.x | sudo -E bash -
sudo apt-get install -y nodejs

Alternatively, for Node.js 8:

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curl -sL https://deb.nodesource.com/setup_8.x | sudo -E bash -
sudo apt-get install -y nodejs

Optional: install build tools
To compile and install native addons from npm you may also need to install build tools:

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sudo apt-get install -y build-essential

Enterprise Linux and Fedora

Including Red Hat® Enterprise Linux® / RHEL, CentOS and Fedora.
On RHEL, CentOS or Fedora, for Node.js v6 LTS:

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curl --silent --location https://rpm.nodesource.com/setup_6.x | sudo bash -

Alternatively for Node.js 8:

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curl --silent --location https://rpm.nodesource.com/setup_8.x | sudo bash -

Then install:

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sudo yum -y install nodejs

Optional: install build tools
To compile and install native addons from npm you may also need to install build tools:

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sudo yum install gcc-c++ make
# or: sudo yum groupinstall 'Development Tools'