ch17.htm

linux-unix130.linux.and.unix.ebooks130 linux and unix ebookslinuxLearning Linux - Collection of 12 E

switches, not surprisingly, to Roman italics. To return to the normal Roman font,

the command <TT>.ft R</TT> is used, although on most systems, <TT>.ft</TT> by itself

will suffice:<FONT COLOR="#0066FF"></FONT>

<PRE><FONT COLOR="#0066FF">This is in normal Roman font.

.ft B

This is bold.

.ft I

This is italics.

.ft

This is back to normal Roman font.

</FONT></PRE>

<P>You can switch fonts with a line-embedded command, too, using <TT>\f</TT> followed

by either <TT>I</TT> or <TT>B</TT>, switching back with <TT>R</TT> to the normal

font:<FONT COLOR="#0066FF"></FONT>

<PRE><FONT COLOR="#0066FF">This is normal, \fBbold\fR and \fIitalics\fR.

</FONT></PRE>

<P>Because underline wasn't supported on most system printers, underlined text was

converted to italics. The underline command <TT>.ux</TT> would italicize the next

x lines of text.</P>

<P>Because we now have many thousands more fonts to work with than Roman, we must

be able to change fonts within <TT>groff</TT>. The command to change fonts is <TT>.fp</TT>

(font physically mounted), which also requires a number to indicate what position

the font was mounted in the phototypesetter (old stuff, isn't it?). For example,

if Helvetica were mounted in font position three and we referred to it by the font

letter <TT>H</TT>, the command<FONT COLOR="#0066FF"></FONT>

<PRE><FONT COLOR="#0066FF">.fp 3 H

</FONT></PRE>

<P>would instruct the phototypesetter to switch to Helvetica in font position three.

<TT>groff</TT> still retains these old-style commands.

<H4 ALIGN="CENTER"><A NAME="Heading8<FONT COLOR="#000077">Indenting and Line

Length</FONT></H4>

<P>The line length is set to default to 6.5 inches within <TT>groff</TT>. To override

this value, the <TT>.ll</TT> (line length) command is used with an argument indicating

the units. For example, the command<FONT COLOR="#0066FF"></FONT>

<PRE><FONT COLOR="#0066FF">.ll 7i

</FONT></PRE>

<P>switches <TT>groff</TT> to use a seven-inch line length. The maximum length accepted

is usually about 7.5 inches, so to use paper wider than that you have to move the

left margin over to compensate with the <TT>.po</TT> (page offset) command. The value

<TT>.po 0</TT> sets the left margin as far over as is possible.</P>

<P>To indent text, you use the <TT>.in</TT> (indent) command. It takes a number and

an indicator of the units as arguments, as the following example shows:<FONT COLOR="#0066FF"></FONT>

<PRE><FONT COLOR="#0066FF">This is normal stuff.

.in 0.75I

This is indented three-quarters of an inch.

</FONT></PRE>

<P>To move the right margin to the left so that you can make a distinctive block

of text within a normal chunk, you use the <TT>.ll</TT> (line length) command you

saw earlier:<FONT COLOR="#0066FF"></FONT>

<PRE><FONT COLOR="#0066FF">This is normal text, and goes on and on.

Even more text that continues the tradition.

.in 1i

.ll -1i

This is now indented one inch to the left, and the

right margin is indented one inch from the normal right

margin.  This makes the text stand out a little.

.in -1i

.ll +1i

And this is back to normal.  The block will stand out nicely

amongst all this normal text.

</FONT></PRE>

<P>You will notice that we used relative movements of plus and minus a value in this

example to make it easier. This way, we don't have to measure the page. You can revert

to original values with the command <TT>.in</TT> and <TT>.ll</TT> with no arguments,

as well.</P>

<P>An indent and line-length change is effective until the next command changes it.

Sometimes you want to affect only a single line, though. If you want to indent only

a single line, use the <TT>.ti</TT> (temporary indent) command:<FONT COLOR="#0066FF"></FONT>

<PRE><FONT COLOR="#0066FF">This is really fine stuff.  You can tell, `cause I'm

still awake.

.ti 3i

This line is temporarily indented by three inches, but the

next line will be back to normal.

</FONT></PRE>

<P>Tabs are used to set column output. Usually, tabs are used with <TT>groff</TT>

only for unfilled text, which means material you would display in columns. Tab stops

are set, by default, every half inch. To override these values, you use the <TT>.ta</TT>

(tab) command. The command<FONT COLOR="#0066FF"></FONT>

<PRE><FONT COLOR="#0066FF">.ta 1i 2i 3i 4i 5i 6i

</FONT></PRE>

<P>sets the tabs at every inch instead. You can think of the setting of tabs within

<TT>groff</TT> much as they are done on a typewriter, from left to right. Tabs are

usually set for columns of numbers or tables, but the <TT>groff</TT> macro <TT>gtbl</TT>

is much better at this. (You get a look at <TT>gtbl</TT> in the next chapter.)

<H4 ALIGN="CENTER"><A NAME="Heading9<FONT COLOR="#000077">Other Character Controls</FONT></H4>

<P>The <TT>groff</TT> system has special instructions for controlling the size of

individual letters, as well as formulas and special characters such as Greek letters.

However, because <TT>groff</TT> is not needed for most purposes these days, we'll

ignore the capabilities. If you want more information on how to provide these special

features, check the <TT>groff</TT> man pages or consult a good <TT>troff</TT> book.

<H3 ALIGN="CENTER"><A NAME="Heading10<FONT COLOR="#000077">Macros</FONT></H3>

<P>A macro is a shorthand notation for a set of commands or strings. Many commands

used to write man pages are macros. To give a practical example of a <TT>groff</TT>

macro, suppose we want every paragraph to start with a blank line and a temporary

indent of half an inch. The <TT>groff</TT> commands to do this are</P>

<PRE><FONT COLOR="#0066FF">.sp

.ti +.5i

</FONT></PRE>

<P>Instead of typing these two lines every paragraph, we can define a macro of one

character (or more) that does it for us.</P>

<P>To define the macro, we use the <TT>.de</TT> (define) command followed by the

name of the macro and the commands. It would look like this, placed somewhere at

the top of the source code:<FONT COLOR="#0066FF"></FONT>

<PRE><FONT COLOR="#0066FF">.de PP

.sp

.ti +.5I

..

</FONT></PRE>

<P>The last line with two periods indicates the end of the definition. Now, whenever

we use the command <TT>.PP</TT> it will be executed as the lines in the macro.



<DL>

	<DT></DT>

</DL>





<DL>

	<DD>

<HR>

<A NAME="Heading11<FONT COLOR="#000077"><B>WARNING:</B> </FONT>Make sure that

	you don't define a macro with the name of a reserved <TT>groff</TT> command, or the

	macro will not be executed.

<HR>



</DL>



<H3 ALIGN="CENTER"><A NAME="Heading12<FONT COLOR="#000077">Using mm</FONT></H3>

<P>The <TT>mm</TT> (memorandum macros) package is not really part of <TT>nroff</TT>

or <TT>troff</TT>, although both can use it. The <TT>mm</TT> program reads a source

file much as <TT>groff</TT> does and translates it to output. Many of the <TT>mm</TT>

macros are used for man pages. Indeed, many users find the <TT>nroff</TT> and <TT>troff</TT>

commands too awkward or complicated, whereas <TT>mm</TT> is fully able to meet all

their basic formatting needs.</P>

<P>To add <TT>mm</TT> commands, you use the period in the first column as with <TT>groff</TT>.

The <TT>mm</TT> macros are usually quite simple, and easy to work with and use. We

can look at the most important of them here.

<H4 ALIGN="CENTER"><A NAME="Heading13<FONT COLOR="#000077">Paragraphs and Headers</FONT></H4>

<P>Like <TT>groff</TT>, <TT>mm</TT> runs text together when reformatting, regardless

of line breaks in the source file. To force a new paragraph, use the <TT>.P</TT>

command. It forces a line break and adds a blank line to the output. Paragraphs are

usually formatted so that they are flush left.</P>

<P>Headings are created with the <TT>.H</TT> command. For example, the command<FONT

COLOR="#0066FF"></FONT>

<PRE><FONT COLOR="#0066FF">.H This is a Heading

</FONT></PRE>

<P>will create a break, output the heading text in bold, and leave a bit of a space

between the heading and the text that follows it.</P>

<P>There can be seven levels of headings; 1 is the highest and 7 is the lowest. To

specify the heading level, add the number as the first argument after the <TT>.H</TT>

command:<FONT COLOR="#0066FF"></FONT>

<PRE><FONT COLOR="#0066FF">.H 2 This is a level 2 heading

</FONT></PRE>

<P>The <TT>mm</TT> heading macro will number the headings automatically, although

you can suppress the numbering with the <TT>.HU</TT> (heading unnumbered) command.

To reset the numbering (at a section break, for example), use the <TT>.nr</TT> (number

register) command followed by the heading level and the number to use. For example,

the command<FONT COLOR="#0066FF"></FONT>

<PRE><FONT COLOR="#0066FF">.nr H2 1</FONT></PRE>

<P>will restart the numbering of second-level headings at 1.

<H4 ALIGN="CENTER"><A NAME="Heading14<FONT COLOR="#000077">Lists</FONT></H4>

<P>Lists are easily created in <TT>mm</TT> with the <TT>.LI</TT> (list) command and

the <TT>.LE</TT> (list end) command. This creates a bulleted list. For example, the

command<FONT COLOR="#0066FF"></FONT>

<PRE><FONT COLOR="#0066FF">.LI

thing 1

.LI

thing 2

.LE

thing 3

</FONT></PRE>

<P>creates a bulleted list of the three bits of text. You can create a list with

dashes instead of bullets using the <TT>.DL</TT> (dash list) command. The mark list

command, <TT>.ML</TT>, creates a list with the character of your choice.</P>

<P>If you want a numbered list, use the <TT>.AL</TT> (automatic list) command. Lists

with no arguments are created with Arabic numbers. To create an alphabetical list

(A, B, C, and so on), use the macro command <TT>.AL A</TT>. Roman numerals (i, ii,

iii, iv, v, and so on) can be used with the <TT>.AL I</TT> command.</P>

<P>You can nest list types as necessary. For example, the command</P>

<PRE><FONT COLOR="#0066FF">.AL I

.LI

groff

.AL

.LI

macros

.LI

mm

.LE

.LI

gtbl

.LI

geqn

.LE

</FONT></PRE>

<P>will create output that looks like this:<FONT COLOR="#0066FF"></FONT>

<PRE><FONT COLOR="#0066FF">I.  groff

      1. macros

      2. mm

II.   gtbl

III.  geqn

</FONT></PRE>

<P>You have to be careful when terminating each list with an <TT>.LE</TT> command

to ensure that you terminate the proper one. Experimentation and practice help you

get the hang of this. You may have noticed that it takes a lot of commands to make

a little list!

<H4 ALIGN="CENTER"><A NAME="Heading15<FONT COLOR="#000077">Font Changes</FONT></H4>

<P>Changing fonts with <TT>mm</TT> is quite simple. When working from a period command,

the command <TT>.B</TT> (bold) creates bold text until an <TT>.R</TT> (restore) command,

while 



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