The first essays of the school year are coming due, and with the essays comes the need to outline and plan. GNU/Linux users are fortunate to have a number of outlining applications from which to choose. True, some outliners have become obsolete, and you will be lucky to get programs like GNOME-Think or the once-popular KnowIt to run on a modern distribution. But you can still choose among OpenOffice.org, TuxCards, NoteCase, Emacs, and VimOutliner for doing your planning.
OpenOffice.org Writer and Impress
OpenOffice.org offers two tools for outlining. In Writer, you can outline by using the Heading styles. To edit an outline, press the F5 key to open the floating window called the Navigator. Under Headings you will find a tree view of all the headings you've used in your document. You can expand or collapse the tree view as needed, and, using the tools in the icon bar, promote or demote headings. You can also reposition them on the tree, which also repositions subordinate sections -- in other words, when you move a paragraph that uses the Heading 1 style, all Heading 2 or 3 styles until the next Heading 1 style move with it.
The one drawback to outlining in Writer is that you see only headings, not any paragraphs of content. However, you can change that by going to Tools -> Outline Numbering and changing one of the defined styles to Text Body -- I suggest Level 4, since you rarely need more than three levels of headings. If you use the Text Body style for your content, then its paragraphs will also appear under Headings in the Navigator.
Alternatively, you can open an Impress document and go to View -> Outline, and close the Slides pane on the left side of the editing window, since you don't care what your outline looks like in a slide show. All headings are at the same level when you edit them, but you can use the four arrow buttons to change each heading's level, or to change its position. Note, though, that the Move Up and Move Down arrows completely ignore the hierarchy, and move an entry exactly one step up, regardless of what level that places it at. You have to keep pressing the arrow keys, and not lose track of the level on which you want to place the item. For anything but simple outlining, you probably want to use something other than Impress.
Although primarily designed for taking notes, Tuxcards is one of the most popular Linux outlining tools.
Tuxcards has the virtue of simplicity. On the left is a pane for adding and manipulating headings, and, on the right, a pane for content for the currently selected heading. YOu can use basic text formatting, such as font selection and size and bold or italic weights. You can also get a word count.
This arrangement means that you can easily plan then write. When you are finished, you can export the result to HTML, then open it in a word processor like Abiword for final formatting and the addition of any footnotes.
NoteCase is similar to Tuxcards in basic functionality and layout. However, it includes a few extras, such as the ability to tag entries -- or "nodes," as it calls them -- in the tree, or to mark them as complete or add icons to help identify them. You can also add links or pictures, or display just the tree or the content pane so you can focus on the task at hand. Other useful features include the ability to sort child nodes and to print only selected branches of the tree. Despite these extra features, NoteCase requires minimal learning before you can start using it with some expertise.
VimOutliner and Emacs
If you don't want to use a separate application for outlines, you can also use either of GNU/Linux's basic text editors, using key commands to show, hide, or move headings, enter content, or do any of the other things you can do with other outlining applications. However, learning to use each of these applications for outlining can take a while if you do not already use it.
Emacs has an existing Outline mode that you can start with the command
M-x outline-mode. From there, you can work with the detailed documentation to learn the basic keyboard shortcuts as well as how to do more advanced operations, such as using Roman numerals in the outline.
By contrast,VimOutliner is much harder to learn. A plugin for the Vim editor, it remains so poorly documented that most people I know who use it have apparently learned it from someone else, rather than from information on the Internet. If you want to give it a try, you can learn the basics from the VimOutliner HowTo and "Vim 6: A Great Linux Outliner," as well as "VimOutliner for Beginners."
VimOutliner takes a while to learn, but those who take the trouble are often pleased that they did. Besides the usual features of outliners, it features unique colors for each level, and, once you master the keystrokes, perhaps the fastest input of any of the tools mentioned here. By comparison, Emacs' outlines are rather basic, although, to be fair, both Emacs and VimOutliner can be tweaked or supplemented by other plugins in a number of ways.
Choosing an outliner
Which outliner you choose depends heavily on your computing habits. For those who want a dedicated program that requires next to no learning, TuxCards and NoteCase are both efficient tools. NoteCase has a slight edge in features, and is definitely still in development. Both, however, have the disadvantage of requiring export into a word processor if you need formatting.
OpenOffice.org's tools are more basic, but have the advantage of familiarity, as well as being in the same application as you will be formatting your finished document. Assuming you have basic office application experience, you should find them almost as easy to learn as TuxCards and NoteCase, except for the fact that their controls are not quite so straightforward.
By contrast, Emacs and VimOutliner are for those comfortable at the command line. If you already use Emacs and Vim, you will find both relatively easy to use for outlining, although you will still have to learn some new keystrokes. However, if you are new to these editors, you may not want to learn all that is necessary just to do an outline.
Try one of these tools for a while, and, if it doesn't suit you, move on to another. Considering how many choices you have, you should eventually find at least one to your liking.