:h usr_06.txt

usr_06.txt For Vim version 7.4. Last change: 2009 Oct 28LINK

VIM USER MANUAL - by Bram Moolenaar

Using syntax highlighting

Black and white text is boring. With colors your file comes to life. This

not only looks nice, it also speeds up your work. Change the colors used for

the different sorts of text. Print your text, with the colors you see on the

screen.

06.1 Switching it on

06.2 No or wrong colors?

06.3 Different colors

06.4 With colors or without colors

06.5 Printing with colors

06.6 Further reading

Next chapter: usr_07.txt Editing more than one file

Previous chapter: usr_05.txt Set your settings

Table of contents: usr_toc.txt

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06.1 Switching it onLINK

It all starts with one simple command:

:syntax enable

That should work in most situations to get color in your files. Vim will

automagically detect the type of file and load the right syntax highlighting.

Suddenly comments are blue, keywords brown and strings red. This makes it

easy to overview the file. After a while you will find that black&white text

slows you down!

If you always want to use syntax highlighting, put the ":syntax enable"

command in your vimrc file.

If you want syntax highlighting only when the terminal supports colors, you

can put this in your vimrc file:

if &t_Co > 1

syntax enable

endif

If you want syntax highlighting only in the GUI version, put the ":syntax

enable" command in your gvimrc file.

==============================================================================

06.2 No or wrong colors?LINK

There can be a number of reasons why you don't see colors:

- Your terminal does not support colors.

Vim will use bold, italic and underlined text, but this doesn't look

very nice. You probably will want to try to get a terminal with

colors. For Unix, I recommend the xterm from the XFree86 project:

xfree-xterm.

- Your terminal does support colors, but Vim doesn't know this.

Make sure your $TERM setting is correct. For example, when using an

xterm that supports colors:

setenv TERM xterm-color

or (depending on your shell):

TERM=xterm-color; export TERM

The terminal name must match the terminal you are using. If it

still doesn't work, have a look at xterm-color, which shows a few

ways to make Vim display colors (not only for an xterm).

- The file type is not recognized.

Vim doesn't know all file types, and sometimes it's near to impossible

to tell what language a file uses. Try this command:

:set filetype

If the result is "filetype=" then the problem is indeed that Vim

doesn't know what type of file this is. You can set the type

manually:

:set filetype=fortran

To see which types are available, look in the directory

$VIMRUNTIME/syntax. For the GUI you can use the Syntax menu.

Setting the filetype can also be done with a modeline, so that the

file will be highlighted each time you edit it. For example, this

line can be used in a Makefile (put it near the start or end of the

file):

# vim: syntax=make

You might know how to detect the file type yourself. Often the file

name extension (after the dot) can be used.

See new-filetype for how to tell Vim to detect that file type.

- There is no highlighting for your file type.

You could try using a similar file type by manually setting it as

mentioned above. If that isn't good enough, you can write your own

syntax file, see mysyntaxfile.

Or the colors could be wrong:

- The colored text is very hard to read.

Vim guesses the background color that you are using. If it is black

(or another dark color) it will use light colors for text. If it is

white (or another light color) it will use dark colors for text. If

Vim guessed wrong the text will be hard to read. To solve this, set

the 'background' option. For a dark background:

:set background=dark

And for a light background:

:set background=light

Make sure you put this _before_ the ":syntax enable" command,

otherwise the colors will already have been set. You could do

":syntax reset" after setting 'background' to make Vim set the default

colors again.

- The colors are wrong when scrolling bottom to top.

Vim doesn't read the whole file to parse the text. It starts parsing

wherever you are viewing the file. That saves a lot of time, but

sometimes the colors are wrong. A simple fix is hitting CTRL-L. Or

scroll back a bit and then forward again.

For a real fix, see :syn-sync. Some syntax files have a way to make

it look further back, see the help for the specific syntax file. For

example, tex.vim for the TeX syntax.

==============================================================================

06.3 Different colors :syn-default-overrideLINK

If you don't like the default colors, you can select another color scheme. In

the GUI use the Edit/Color Scheme menu. You can also type the command:

:colorscheme evening

"evening" is the name of the color scheme. There are several others you might

want to try out. Look in the directory $VIMRUNTIME/colors.

When you found the color scheme that you like, add the ":colorscheme" command

to your vimrc file.

You could also write your own color scheme. This is how you do it:

1. Select a color scheme that comes close. Copy this file to your own Vim

directory. For Unix, this should work:

!mkdir ~/.vim/colors

!cp $VIMRUNTIME/colors/morning.vim ~/.vim/colors/mine.vim

This is done from Vim, because it knows the value of $VIMRUNTIME.

2. Edit the color scheme file. These entries are useful:

term attributes in a B&W terminal

cterm attributes in a color terminal

ctermfg foreground color in a color terminal

ctermbg background color in a color terminal

gui attributes in the GUI

guifg foreground color in the GUI

guibg background color in the GUI

For example, to make comments green:

:highlight Comment ctermfg=green guifg=green

Attributes you can use for "cterm" and "gui" are "bold" and "underline".

If you want both, use "bold,underline". For details see the :highlight

command.

3. Tell Vim to always use your color scheme. Put this line in your vimrc:

colorscheme mine

If you want to see what the most often used color combinations look like, use

this command:

:runtime syntax/colortest.vim

You will see text in various color combinations. You can check which ones are

readable and look nice.

==============================================================================

06.4 With colors or without colorsLINK

Displaying text in color takes a lot of effort. If you find the displaying

too slow, you might want to disable syntax highlighting for a moment:

:syntax clear

When editing another file (or the same one) the colors will come back.

:syn-offLINK

If you want to stop highlighting completely use:

:syntax off

This will completely disable syntax highlighting and remove it immediately for

all buffers.

:syn-manualLINK

If you want syntax highlighting only for specific files, use this:

:syntax manual

This will enable the syntax highlighting, but not switch it on automatically

when starting to edit a buffer. To switch highlighting on for the current

buffer, set the 'syntax' option:

:set syntax=ON

==============================================================================

06.5 Printing with colors syntax-printingLINK

In the MS-Windows version you can print the current file with this command:

:hardcopy

You will get the usual printer dialog, where you can select the printer and a

few settings. If you have a color printer, the paper output should look the

same as what you see inside Vim. But when you use a dark background the

colors will be adjusted to look good on white paper.

There are several options that change the way Vim prints:

To print only a range of lines, use Visual mode to select the lines and then

type the command:

v100j:hardcopy

"v" starts Visual mode. "100j" moves a hundred lines down, they will be

highlighted. Then ":hardcopy" will print those lines. You can use other

commands to move in Visual mode, of course.

This also works on Unix, if you have a PostScript printer. Otherwise, you

will have to do a bit more work. You need to convert the text to HTML first,

and then print it from a web browser.

Convert the current file to HTML with this command:

:TOhtml

In case that doesn't work:

:source $VIMRUNTIME/syntax/2html.vim

You will see it crunching away, this can take quite a while for a large file.

Some time later another window shows the HTML code. Now write this somewhere

(doesn't matter where, you throw it away later):

:write main.c.html

Open this file in your favorite browser and print it from there. If all goes

well, the output should look exactly as it does in Vim. See 2html.vim for

details. Don't forget to delete the HTML file when you are done with it.

Instead of printing, you could also put the HTML file on a web server, and let

others look at the colored text.

==============================================================================

06.6 Further readingLINK

usr_44.txt Your own syntax highlighted.

syntax All the details.

==============================================================================

Next chapter: usr_07.txt Editing more than one file