Text Processing in Unix - PowerPoint PPT Presentation

Text Processing in Unix

• Unix has never had a standard word processing system
• Although several word processors are now available (WordPerfect, StarOffice, ApplixWare) none has reached the status of a standard
• Portability is an issue
• Unix has traditionally relied upon text processors instead
• roff
• nroff/troff
• TeX

• Text processing is a two step process
• First the document is created using a text editor such as vi
• Document contains plain text and formatting codes
• Second step is to print the document through a formatter, such as nroff
• The formatter interprets the codes embedded in the document so that it is printed according to your specification
• Note that the editor does not format, and the formatter is of no use for editing; they are two distinct operations

Text

Editing

Document

File

Text

Formatting

The Great

AmericanNovel

Final

Doc

• roff-like formatting systems describe actions you want to have performed on your text
• indent
• italicize
• bold
• They use very primitive, low-level commands
• It would be nice instead to define the type of text (paragraph, footnote, heading) and externally specify the particular format you want applied to this type of text

• Like Postscript, nroff is a programming language
• It has a set of preprocessors, like C
• It has macros
• It has a full set of registers
• As with Unix, most people do not need to understand the full programming aspects in order to effectively use nroff, any more than you need to know C to use Unix

• Macros translate high level result oriented commands into low level commands
• Start paragraph
• Start heading
• Start section
• There are two principal macro packages
• -mm macro memorandum
• -ms
• -mm is the more robust of the two packages
• While -ms was designed to do everything, -mm was designed for robustness
• Many simple errors in -ms lead to mystifying results while -mm usually provides helpful error messages

• Although nroff is a powerful formatter, it can’t do everything
• You can set tabs but nroff can’t analyze the widths of columns and automatically set widths
• nroff has some ability for drawing lines and boxes but it is hard to do manually
• Although nroff has access to mathematical symbols, building equations directly is too hard
• Preprocessors are used to extend the abilities of nroff
• Preprocessors are designed to address a specific typesetting specialty, such as equations or line drawings

• Preprocessors work in "the Unix way"
• They are filters
• They perform one specific function rather than causing nroff to bloat
• They are used with pipes
• tbl mydoc | troff
• Four common preprocessors
• tbl - for managing tabular data
• eqn (or neqn) - for typesetting mathematical equations
• refer - for bibliographical references
• pic - for creating line drawings

• nroff contains two types of commands
• dot commands
• embedded commands
• Dot Commands
• Must stand alone on a line
• Have a period (dot) as the first character on the line
• Many dot commands accept one or more arguments to give them information about what to do
• Example: .sp produces one extra (blank) line of output
• .sp 3 produces three extra blank lines
• At least one space or tab must separate the arguments

• Embedded commands start with a backslash ( \ )
• Often used to access a special character
• Most accept an argument which must immediately follow the command without any intervening space
• Some features, such as point size or font changes, can be done with either a dot or embedded command
• In general, dot commands are used to control global features
• Embedded commands used to control local features
• .\" is used to protect remarks from being printed

• .sp controls vertical spacing.
• By itself, .sp inserts a blank line
• .sp num enters num blank lines
• .sp numi adds num inches of blank space
• Absolute movement is also possible
• .sp | 3i moves to the position 3 inches from the top of page
• .sp | -2i moves to 2 inches from the bottom of page
• Note: most macro packages turn on no-space mode after printing page headers so any top-of-page requests will be ignored. If you always want to produce the space, put a .rs on the line preceding the .sp command

• Default is generally about 20% more than the font point size
• To change, use .vs psp, where ps is point size, ie; .vs 12p for 12 point spacing (12/72 inch)
• .ls controls line spacing
• .ls 2v causes double spaced output

• .ne 2v tests to see if there are at least two lines of space remaining on the page
• If there isn't enough space, the page position is advanced to the next trap, which usually prints the footer and advances to the next page
• .ne is used to avoid widows, where the first or last line of a paragraph is isolated on a different page from the rest of the paragraph

• Measured in ems (approximately the width of an M)
• .in 5m indents all following text by 5 ems
• .ti controls temporary indent for the next line
• .br causes a break in the text-filling process
• Often used in header/return address portion of a letter to separate lines

Ken Frazer

.br

PO Box 1234

.br

Coppell, TX

• .ta sets the tab stops and requires arguments
• .ta 8n 16n 24n 32n 40n sets tabs every 8 character positions
• Can also use other measurement units
• .ta .5i 1i 1.5i 2i
• Tabs remain in effect until changed so in theory, you only need to set them once
• However, in practice you should set them every time you use them because the standard macro packages and preprocessors fiddle with them all the time

• \| and \^ are narrow space codes
• \| is 1/6 em, \^ is 1/12 em
• \c is the end-of-line continuation mark
• Normally an end-of-line character is converted to a space when the lines are stitched together. When a \c is used at the end of a line, the space is discarded so the following line is attached to the current line without an intervening space.

• .na and .ad control the adjustment of the margins
• .na (no adjust) causes nroff to stop adjusting margins. Words will still be collected to form an output line but intervening spaces will not be added to make the margins align.
• .ad tells nroff to resume adjusting margins
• .ce centers the following input line(s) until a .ce 0 command is encountered
• Input lines following the .ce command are not filled

• .nf causes nroff to stop collecting input lines to produce appropriately long output lines
• .fi tells nroff to resume filling lines
• .nf can be used instead of .br for producing letter headings

.nf

Ken Frazer

PO Box 1234

Coppell, TX

.fi

.sp 2

Dear Alice,

• .ft is used to switch fonts
• Fonts are referred to by either number or by one- or two-character names
• 1 is Times Roman
• 2 is Times Roman italic
• R is also Times Roman
• RI is Times Roman italic
• \fn is another way to switch fonts
• \f1plain\f2italics\f3bold\f1 will produce plainitalicsbold

• nroff will automatically hyphenate words at the end of a line, but like any automatic hyphenator, it sometimes makes mistakes
• .hn turns off automatic hyphenation
• .hy enables automatic hyphenation. It accepts a numeric argument that controls when hyphenation is used
• .hy 2 disables hyphenation for the last line of a page
• .hy 4 disables splitting off the last two characters of a word
• .hy 8 disables splitting off the first two characters of a word

• .hw de-vice proc-ess cata-logue un-known trans-portable

• nroff has two commands to switch from one input file to another
• .so switches from from the current file to the file named as an argument. When the inserted file is completely read, nroff returns to the original file and continues reading from the point just past the .so.
• .nx switches from the current file to the file named as an argument. All processing stops when the new file is completely read. Any text in the original file that follows the .nx command will not be processed.

• -ms was the first widely used macros package
• To use:
• nroff -ms inputfile | lpr

• .NH n produces a numbered heading

.NH n

text

.LP

• where n is the heading level, text is the heading text, .LP starts a new paragraph
• .SH produces a section heading

.SH

text

.LP

• .PP starts a normal paragraph with first line indented
• .LP starts a normal paragraph with all lines flush left
• .IP label starts an indented paragraph. All lines are indented on the left and the optional label is printed to the left of the first line.
• .XP starts an exdented paragraph. All lines except the first will be indented on the left.

• .1C or .2C switches to one-column (the default) or two-column format
• .DA date prints the date at the bottom of the page. The optional date argument overrides the current date.
• .ND inhibits printing the date at the bottom of the page.
• .OH 'L'C'R' These macros produce Headers and .EH 'L'C'R' Footers on Odd or Even pages. .OF 'L'C'R' Each three-part header consists of .EF 'L'C'R' text L for the left, C for the center,and R for the right. In a header or footer % will print the page number.

• .R Switch font to Roman, italic, or bold. .I wd1 wd2 For I or B, if wd1 is supplied, it .B wd1 wd2 alone will be in italic or bold. If wd2 is supplied, it will follow wd1, without a separating space, and be in the surrounding font.
• .SM Switch to a smaller, normal-size, or .NL larger typeface. .SM or .LG can be .LG repeated to increase the size change.
• .UL word Underline a single word.

• .DS x Display text in no-fill mode. text will be text moved to the following page, leaving a .DE blank region, if it doesn't fit. Optional argument x may be L for a flush-left display, I for a slightly indented display, C for a line-by-line centered display, or B for a block centered display. The default is an indented display.
• .LD Display multipage text..ID .LD replaces DS L.CD .ID replaces DS I .CD replaces DS C

• .KF text will float to the start of the following text page if it doesn't fit on the current page. .KE Following text may be moved forward to fill the bottom of the page.

• .TS text will be processed by the tbl text preprocessor. .TE

• .FS text is a footnote that will be placed at text the bottom of the page. Berkeley -ms .FE allows \** to number footnotes automatically.

• .RP uses the AT&T Released Paper style
• .TM uses the Berkeley Thesis style
• .TL uses text for a title

.TL

text

• .AU specifies an author's name (text) and optional address and phone number (loc and ext, respectively)

.AU loc ext

text

.AI

text

• .AB is used for the abstract

.AB

text

.AE

• .SG inserts the author's signature (name) in the text

• .XS n uses text as a TOC entry, with page number n

.XS n

text

.XE

• .PX prints the table of contents

• Implemented as filters so piping is appropriate
• tbl infile | pic | neqn | nroff | lpr

.TS

center box;

C S

RI L.

Text Preprocessors

.sp .3v

tbl Tables of data

eqn Equations

refer References

pic Line Drawings

.TE

Text Preprocessors

tbl

eqn

refer

pic

Tables of data

Equations

References

Line Drawings

.EQ

int { { e sup {i omega t} + e sup {-i omega t} }

over {2 pi} }

.EN

.PS

box ht .4 wid .6

box ht .6 wid .8 with .c at last box.c

PC: box ht .3 wid 1 with .n at last box.s

“PC” at PC.c + (-.35,0)

box ht .15 wid .3 at PC.c

box ht same at PC.c + (.3,0)

.PE

PC