Org mode

如果插入的图片太宽，可以用类似下面的语句来限制导出 html 或 pdf(latex) 时图片的显示宽度。

#+ATTR_HTML: :width 500px
#+ATTR_LATEX: :width 500pt
[[./images/example.jpg]]

说明：latex 中不支持 px（像素，相对长度）作为长度单位，可以使用 pt（磅，绝对长度，1pt＝1/72 英寸）作为长度单位。它们之间的转换和 DPI（每英寸像素数量）相关。假设 DPI 为 72，那么 1px=1pt。

| Name  | Phone | Age |
|-------+-------+-----|
| Peter |  1234 |  17 |
| Anna  |  4321 |  25 |

以上面表格为例，如何快速插入 horizontal separator line 呢？
方法 1：在第二行中键入|-后按 TAB 键。
方法 2：在第一行中键入|Name|Phone|Age 后按 C-c <RET>.

参考：http://orgmode.org/manual/Built_002din-table-editor.html#Built_002din-table-editor

默认地，数字列是右对齐，而字符列是左对齐。不过，这可以通过在表格第一行（不会导出）加特别的标记来定制对齐方式。如：

#+CAPTION: 定制对齐方式
| <l>   |        <r> |
|       |     右对齐 |
|-------+------------|
| 10    | 这列右对齐 |
| 20000 |     右对齐 |

如何让 org-mode 中表格显示很长的行时不换行，而是隐藏超长部分？

M-x toggle-truncate-lines

但不在表格中的很长的行也会隐藏超长部分。

To insert a vertical bar into a table field, use \vert.

参考：http://orgmode.org/manual/Built_002din-table-editor.html#fn-1

把光标移动到需要排序的列中，执行下面命令即可按此列排序：

M-x org-sort

org mode 中的表格支持数学运算。它底层使用的是 Emacs calc package 的功能。

参考：
Org as a spreadsheet system: a short introduction
Org as a spreadsheet system: using Emacs lisp as formulas
Emacs calc中一些常用统计公式
http://orgmode.org/manual/The-spreadsheet.html

从 Emacs 22 起，内置了一个强大的基于文本的表格（tabel.el 表格），详情可参考Emacs Text-based Tables。
tabel.el 表格能支持一些复杂的特性，如合并或拆分单元格（ M-x table-span-cell 或 M-x table-split-cell ）。tabel.el 表格实例如下：

在 org-mode 中可用下面命令插入或编辑 table.el 表格。

不过，测试时发现 tabel.el 表格不支持“#+CAPTION”的用法。

参考：http://orgmode.org/manual/Cooperation.html

Org mode tables are exported to HTML using the table attributes defined in org-html-table-default-attributes. The default setting makes tables without cell borders and frame. If you would like to change this for individual tables, place something like the following before the table:

#+CAPTION: 这个表格显示全部的边框
#+ATTR_HTML: :border 2 :rules all :frame border

参考：http://orgmode.org/manual/Tables-in-HTML-export.html#Tables-in-HTML-export

在表格前面指定“#+ATTR_HTML: :style font-family:"Courier New", Courier, monospace;”可以设置为导出 html 时使用“等宽”字体。

参考：http://www.w3schools.com/css/css_font.asp

默认地，如果表格有某列的内容过长，在导出 pdf 时，表格会溢出。
如何让其自动换行呢？
方法一（推荐）：在 align 属性中通过 p{'width'} 明确指定列的宽度。如下面例子设置 column1 为左对齐，column2/column3 所占宽度为 0.3/0.4 倍行宽：

#+ATTR_LATEX: :align lp{0.3\linewidth}p{0.4\linewidth}
#+CAPTION: 通过使用tabularx可以使表格中很长的内容自动换行
| column1 | column2                                                               | column3                                                                                                            |
|---------+-----------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------|
| test    | very long long long long long long long long long long long long long | very long long long long long long long long long long long long long long long long long long long long long long |

方法二：
修改表格的环境为 tabularx （注：tabularx 的 width 属性是必须指定的），对过长的那一列指定 align 属性为 X ，这可以使其自动换行。如：

#+ATTR_LATEX: :environment tabularx :width \linewidth :align lXX
#+CAPTION: 通过使用tabularx可以使表格中很长的内容自动换行
| column1 | column2                                                               | column3                                                                                                            |
|---------+-----------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------|
| test    | very long long long long long long long long long long long long long | very long long long long long long long long long long long long long long long long long long long long long long |

采用方法二时，需要把 tabularx 加入到 org-latex-packages-alist 中。

参考：
https://en.wikibooks.org/wiki/LaTeX/Tables
http://orgmode.org/manual/LaTeX-specific-attributes.html

通过指定 :font 属性，可以设置 pdf 表格的字体大小。如：

#+ATTR_LATEX: :font \scriptsize
| Name  | Phone | Age |
|-------+-------+-----|
| Peter |  1234 |  17 |
| Anna  |  4321 |  25 |

下面是一些字体大小的可选设置（从上到下字体变小）：

\Huge
\huge
\LARGE
\Large
\large
\normalsize
\small
\footnotesize
\scriptsize
\tiny

Both in example and in src snippets, you can add a -n switch to the end of the BEGIN line, to get the lines of the example numbered.
You can also add a -r switch which removes the labels from the source code.

指定 -n 可显示源码行号，指定 -r 可对源码行号进行引用。

如图 1 所示 org 源码会导出为：

1: (save-excursion
2:    (goto-char (point-min)))

In line 1 we remember the current position. Line 2 jumps to point-min.

参考：http://orgmode.org/manual/Literal-examples.html

参考：http://orgmode.org/org.html#Header-arguments

Code blocks can be evaluated and the results of evaluation optionally placed in the Org mode buffer. The results of evaluation are placed following a line that begins by default with #+RESULTS and optionally a cache identifier and/or the name of the evaluated code block.

By default, the evaluation facility is only enabled for Lisp code blocks specified as emacs-lisp.

There are a number of ways to evaluate code blocks. The simplest is to press C-c C-c or C-c C-v e with the point on a code block. This will call the org-babel-execute-src-block function to evaluate the block and insert its results into the Org mode buffer.

Named code blocks can be evaluated with a separate #+CALL: line or inline within a block of text.
The syntax of the #+CALL: line is

#+CALL: <name>(<arguments>)
#+CALL: <name>[<inside header arguments>](<arguments>) <end header arguments>

The syntax for inline evaluation of named code blocks is

... call_<name>(<arguments>) ...
... call_<name>[<inside header arguments>](<arguments>)[<end header arguments>] ...

输入 <s 再按 TAB 键，就会自动展开为 #+BEGIN_SRC ... #+END_SRC。类似地，还有其它的一些展开序列。如表 7 所示。

表 8 列出了 Code Blocks 中支持的程序语言。

参考：http://orgmode.org/manual/Languages.html#Languages

The option org-babel-load-languages controls which languages are enabled for evaluation (by default only emacs-lisp is enabled). This variable can be set using the customization interface or by adding code like the following to your emacs configuration.

The following disables emacs-lisp evaluation and enables evaluation of R and ditaa code blocks.

(org-babel-do-load-languages
 'org-babel-load-languages
 '((emacs-lisp . nil)
   (ditaa . t)
   (R . t)))

org 文件可以导出为 pdf。步骤是先生成 tex 文件，再由 LaTex 生成 pdf 文件。

The default LaTeX output is designed for processing with pdftex or latex. The LaTeX exporter can be configured to support alternative TeX engines, see org-latex-pdf-process, and alternative packages, see org-latex-default-packages-alist and org-latex-packages-alist.

参考：http://orgmode.org/manual/LaTeX-and-PDF-export.html#LaTeX-and-PDF-export

参考：http://orgmode.org/manual/Export-settings.html#Export-settings

The key C-c C-c has many purposes in Org. Here is a summary of what this means in different contexts.

• If there are highlights in the buffer from the creation of a sparse tree, or from clock display, remove these highlights.
  
• If the cursor is in one of the special #+KEYWORD lines, this triggers scanning the buffer for these lines and updating the information.
  
• If the cursor is inside a table, realign the table. This command works even if the automatic table editor has been turned off.
  
• If the cursor is on a #+TBLFM line, re-apply the formulas to the entire table.
  
• If the current buffer is a capture buffer, close the note and file it. With a prefix argument, file it, without further interaction, to the default location.
  
• If the cursor is on a target, update radio targets and corresponding links in this buffer.
  
• If the cursor is in a property line or at the start or end of a property drawer, offer property commands.
  
• If the cursor is at a footnote reference, go to the corresponding definition, and vice versa.
  
• If the cursor is on a statistics cookie, update it.
  
• If the cursor is in a plain list item with a checkbox, toggle the status of the checkbox.
  
• If the cursor is on a numbered item in a plain list, renumber the ordered list.
  
• If the cursor is on the #+BEGIN line of a dynamic block, the block is updated.
  
• If the cursor is at a timestamp, fix the day name in the timestamp.
  

参考：http://orgmode.org/manual/The-very-busy-C_002dc-C_002dc-key.html

如果后文要引用前文中的节，可以这样：

 * Section One
  <<sec:one>>

 * Section Two
  <<sec:two>>

I can reference Section One with  [[sec:one]] and [[sec:one][Section One]].

参考：http://stackoverflow.com/questions/16346622/how-can-i-reference-a-section-by-number-in-org-mode-export

使用快捷键 C-c . 或直接执行函数 M-x org-time-stamp 。