elvis.9

Unix操作系统minix 2.0源码

new file.

.ti -0.25i
.B charattr
.br
Many text formatting programs allow you to designate portions of
your text to be underlined, italicized, or boldface by embedding
the special strings \\fU, \\fI, and \\fB in your text.  The special
string \\fR marks the end of underlined or boldface text.

\fIElvis\fR normally treats those special strings just like any other
text.
However, if the \fIcharattr\fR option is on, then \fIelvis\fR will interpret
those special strings correctly, to display underlined or boldface
text on the screen.  (This only works, of course, if your terminal
can display underlined and boldface, and if the TERMCAP entry says
how to do it.)

.ti -0.25i
.B columns
.br
This is a \*(OQread only\*(CQ option.  You cannot change its value, but you
can have \fIelvis\fR print it.  It shows how wide your screen is.

.ti -0.25i
.B directory
.br
Elvis uses temporary files to store changed text.
This option allows you to control where those temporary files will be.
Ideally, you should store them on in fast non-volatile memory,
such as a hard disk.

This option can only be set in the ".exrc" file.

.ti -0.25i
.B errorbells
.br
Normally, \fIelvis\fR will ring your terminal's bell if you make an error.
However, in noerrorbells mode, your terminal will remain silent.

.ti -0.25i
.B exrefresh
.br
The EX mode of \fIelvis\fR writes many lines to the screen.  You can make
\fIelvis\fR either write each line to the screen separately, or save up
many lines and write them all at once.

The exrefresh option is normally on, so each line is written to the
screen separately.

You may wish to turn the exrefresh option off (:se noer) if the
\*(OQwrite\*(CQ system call is costly on your machine, or if you're using a
windowing environment.  (Windowing environments scroll text a lot
faster when you write many lines at once.)

This option has no effect in \fIvi\fR mode.

.ti -0.25i
.B ignorecase
.br
Normally, when \fIelvis\fR searches for text, it treats uppercase letters
as being different for lowercase letters.

When the ignorecase option is on, uppercase and lowercase are treated
as equal.

.ti -0.25i
.B keytime
.br
The arrow keys of most terminals send a multi-character sequence.
It takes a measurable amount of time for these sequences to be
transmitted.  The keytime option allows you to control the maximum
amount of time to allow for an arrow key (or other mapped key) to
be received in full.

The default keytime value is 2.  Because of the way 
.Ux
timekeeping works, the actual amount of time allowed will vary slightly, but it
will always be between 1 and 2 seconds.

If you set keytime to 1, then the actual amount of time allowed will
be between 0 and 1 second.  This will generally make the keyboard's
response be a little faster (mostly for the ESC key), but on those
occasions where the time allowed happens to be closer to 0 than 1
second, \fIelvis\fR may fail to allow enough time for an arrow key's
sequence to be received fully.  Ugh.

As a special case, you can set keytime to 0 to disable this time
limit stuff altogether.  The big problem here is:  If your arrow
keys' sequences start with an ESC, then every time you hit your ESC
key \fIelvis\fR will wait... and wait... to see if maybe that ESC was
part of an arrow key's sequence.

NOTE: this option is a generalization of the timeout option of the
real vi.

.ti -0.25i
.B keywordprg
.br
\fIElvis\fR has a special keyword lookup feature.  You move the cursor
onto a word, and hit shift-K, and \fIelvis\fR uses another program to
look up the word and display information about it.

This option says which program gets run.  It should contain the full
pathname of the program; your whole execution path is \fInot\fR checked.

The default value of this option is \fI/usr/bin/ref\fR, which is a
program that looks up the definition of a function in C.  It looks
up the function name in a file called \*(OQrefs\*(CQ which is created by
ctags.

You can substitute other programs, such as an English dictionary
program or the online manual.  \fIelvis\fR runs the program, using the
keyword as its only argument.  The program should write information
to stdout.  The program's exit status should be 0, unless you want
\fIelvis\fR to print \*(OQ<<< failed >>>".

.ti -0.25i
.B lines
.br
This \*(OQread only\*(CQ option shows how many lines you screen has.

.ti -0.25i
.B list
.br
Normally (in \*(OQnolist" mode) \fIelvis\fR will expand tabs to the proper
number of spaces on the screen, so that the file appears the same would it would
be if you printed it or looked at it with \fImore\fR.

Sometimes, though, it can be handy to have the tabs displayed as \*(OQ^I".
In \*(OQlist" mode, \fIelvis\fR does this, and also displays a \*(OQ$"
after the end of the line.

.ti -0.25i
.B magic
.br
The search mechanism in \fIelvis\fR can accept \*(OQregular 
expressions\*(CQ\(emstrings in which certain characters have special meaning.
The magic option is normally on, which causes these characters to
be treated specially.
If you turn the magic option off (:se noma), then all characters
except ^ and $ are treated literally.   ^ and $ retain their special
meanings regardless of the setting of magic.

.ti -0.25i
.B paragraphs
.br
The { and } commands move the cursor forward or backward in increments
of one paragraph.  Paragraphs may be separated by blank lines, or by
a \*(OQdot\*(CQ command of a text formatter.  Different text formatters use
different \*(OQdot\*(CQ commands.  This option allows you to configure \fIelvis\fR
to work with your text formatter.

It is assumed that your formatter uses commands that start with a
".\*(CQ character at the front of a line, and then have a one- or
two-character command name.

The value of the paragraphs option is a string in which each pair
of characters is one possible form of your text formatter's paragraph
command.

.ti -0.25i
.B readonly
.br
Normally, \fIelvis\fR will let you write back any file to which you have
write permission.  If you do not have write permission, then you
can only write the changed version of the file to a \fIdifferent\fR
file.

If you set the readonly option, then \fIelvis\fR will pretend you do not
have write permission to \fIany\fR file you edit.  It is useful when
you really only mean to use \fIelvis\fR to look at a file, not to change
it.  This way you cannot change it accidentally.

This option is normally off, unless you use the \*(OQview\*(CQ alias of \fIelvis\fR.
\*(OQView\*(CQ is like \fIvi\fR except that the readonly option is on.

.ti -0.25i
.B report
.br
Commands in \fIelvis\fR may affect many lines.  For commands that affect
a lot of lines, \fIelvis\fR will output a message saying what was done and
how many lines were affected.  This option allows you to define
what \*(OQa lot of lines\*(CQ means.  The default is 5, so any command which
affects 5 or more lines will cause a message to be shown.

.ti -0.25i
.B scroll
.br
The CTRL-U and CTRL-D keys normally scroll backward or forward
by half a screenful, but this is adjustable.  The value of this option
says how many lines those keys should scroll by.

.ti -0.25i
.B sections
.br
The [[ and ]] commands move the cursor backward or forward in
increment of 1 section.  Sections may be delimited by a { character
in column 1 (which is useful for C source code) or by means of
a text formatter's \*(OQdot\*(CQ commands.

This option allows you to configure \fIelvis\fR to work with your text
formatter's \*(OQsection\*(CQ command, in exactly the same way that the
paragraphs option makes it work with the formatter's \*(OQparagraphs"
command.

.ti -0.25i
.B shell
.br
When \fIelvis\fR forks a shell (perhaps for the :! or :shell commands)
this is the program that is uses as a shell.  This is \fI/bin/sh\fR
by default, unless you have set the SHELL environment variable,
it which case the default value is copied from the environment.

.ti -0.25i
.B shiftwidth
.br
The < and > commands shift text left or right by some uniform number
of columns.  The shiftwidth option defines that uniform number.
The default is 8.

.ti -0.25i
.B sidescroll
.br
For long lines, \fIelvis\fR scrolls sideways.  (This is different from
the real \fIvi\fR, which wraps a single long line onto several rows of
the screen.)
To minimize the number of scrolls needed, \fIelvis\fR moves the screen
sideways by several characters at a time.  The value of this option
says how many characters' widths to scroll at a time.
Generally, the faster your screen can be redrawn, the lower the value
you will want in this option.

.ti -0.25i
.B sync
.br
If the system crashes during an edit session, then most of your work
can be recovered from the temporary file that \fIelvis\fR uses to store
changes.  However, sometimes 
.MX
will not copy changes to the
hard disk immediately, so recovery might not be possible.  The [no]sync
option lets you control this.
In nosync mode (which is the default), \fIelvis\fR lets the operating system
control when data is written to the disk.  This is generally faster.
In sync mode, \fIelvis\fR forces all changes out to disk every time you make
a change.  This is generally safer, but slower.

.ti -0.25i
.B tabstop
.br
Tab characters are normally 8 characters wide, but you can change
their widths by means of this option.

.ti -0.25i
.B term
.br
This \*(OQread only\*(CQ option shows the name of the termcap entry that
\fIelvis\fR is using for your terminal.

.ti -0.25i
.B vbell
.br
If your termcap entry describes a visible alternative to ringing
your terminal's bell, then this option will say whether the visible
version gets used or not.  Normally it will be.

If your termcap does NOT include a visible bell capability, then
the vbell option will be off, and you cannot turn it on.

.ti -0.25i
.B warn
.br
\fIElvis\fR will normally warn you if you run a shell command without saving
your changed version of a file.
The \*(OQnowarn" option prevents this warning.

.ti -0.25i
.B wrapmargin
.br
Normally (with wrapmargin=0) \fIelvis\fR will let you type in extremely long
lines, if you wish.
However, with wrapmargin set to something other that 0 (wrapmargin=65
is nice), \fIelvis\fR will automatically cause long lines to be \*(OQwrapped"
on a word break for lines longer than wrapmargin's setting.

.ti -0.25i
.B wrapscan
.br
Normally, when you search for something, \fIelvis\fR will find it no matter
where it is in the file.  \fIelvis\fR starts at the cursor position, and
searches forward.  If \fIelvis\fR hits EOF without finding what you're
looking for, then it wraps around to continue searching from line 1.

If you turn off the wrapscan option (:se nows), then when \fIelvis\fR hits
EOF during a search, it will stop and say so.
.in -0.25i
.SS "Cflags"
.PP
\fIElvis\fR uses many preprocessor symbols to control compilation.
Most of these flags allow you to disable small sets of features.
\s-2MINIX\s0-ST users will probably want all features enabled, but
\s-2MINIX\s0-PC users will have to disable one or two feature sets
because otherwise \fIelvis\fR would be too large to compile and run.

These symbols can be defined via flags passed to the compiler.
The best way to do this is to edit the Makefile, and append the flag
to the \*(OQCFLAGS=\*(CQ line.
After you do that, you must recompile elvis completely by saying
.HS
.Cx "make  clean"
.br
.Cx "make"
.HS
.in +0.25i
.ti -0.25i
.B \(enDM_SYSV
.br
This flag causes \fIelvis\fR to use System-V ioctl() calls for controlling
your terminal; normally it uses v7/BSD/\s-2MINIX\s0 ioctl() calls.

.ti -0.25i
.B \(enDDATE
.br
The symbol DATE should be defined to look like a string constant,
giving the date when \fIelvis\fR was compiled.
This date is reported by the \*(OQ:version\*(CQ command.

You can also leave DATE undefined, in which case \*(OQ:version\*(CQ will not
report the compilation date.

.ti -0.25i
.B \(enDCRUNCH
.br
This flag causes several large often-used macros to be replaced by
equivalent functions.
This saves about 4K of space in the \*(OQ.text\*(CQ segment, and it does not
cost you any features.

.ti -0.25i
.B \(enDDEBUG
.br
This adds many internal consistency checks and the \*(OQ:debug\*(CQ 
and \*(OQ:validate\*(CQ
commands.  It increases the size of \*(OQtext\*(CQ by about 5K bytes.

.ti -0.25i
.B \(enDNO_CHARATTR
.br
This permanenently disables the \*(OQcharattr\*(CQ option.
It reduces the size of \*(OQ.text\*(CQ by about 850 bytes.

.ti -0.25i
.B \(enDNO_RECYCLE
.br
Normally, \fIelvis\fR will recycle space in the temporary file which contains
totally obsolete text.
The \fB\(enDNO_RECYCLE\fR option disables this, making your \*(OQ.text\*(CQ  segment 
smaller by about 1K but also permitting the temporary file to grow very 
quickly.
If you have less than two megabytes of free space on your disk,
then do not even consider using this flag.

.ti -0.25i
.B \(enDNO_SENTENCE
.br
This leaves out the \*(OQ(\*(CQ and \*(OQ)\*(CQ visual commands, and 
removes the code that allows the \*(OQ[[\*(CQ, \*(OQ]]\*(CQ, \*(OQ{\*(CQ, 
and \*(OQ}\*(CQ commands to recognize \fRnroff\fR macros.
The \*(OQ[[\*(CQ and \*(OQ]]\*(CQ commands will still move to the start of 
the previous/next C function source code, though, and \*(OQ{\*(CQ 
and \*(OQ}\*(CQ will move to the previous/next blank line.
This saves about 650 bytes from the \*(OQ.text\*(CQ segment.

.ti -0.25i
.B \(enDNO_CHARSEARCH
.br
This leaves out the visual commands which locate a given character in the
current line: \*(OQf\*(CQ, \*(OQt\*(CQ, \*(OQF\*(CQ, \*(OQT\*(CQ, \*(OQ;\*(CQ, and \*(OQ,\*(CQ.
This saves about 900 bytes.

.ti -0.25i
.B \(enDNO_EXTENSIONS
.br
This leaves out the \*(OQ:mkexrc\*(CQ command, and the \*(OQK\*(CQ and \*(OQ#\*(CQ visual commands.
Other extensions are either inherent in the design of \fIelvis\fR,
or are too tiny to be worth removing.
This saves about 500 bytes.

.ti -0.25i
.B \(enDNO_MAGIC
.br
This permanently disables the \*(OQmagic\*(CQ option, so that most 
meta-characters in a regular expression are not recognized.  
This saves about 3K bytes from the \*(OQ.text\*(CQ segment.
.HS
.in -0.25i
.SS "Termcap"
\fIElvis\fR can use standard termcap entries,
but it also recognizes and uses several extra capabilities, if you give them.
All of these are optional.
.nf
.in +0.25i
.ta 1.5i
.HS
\fBCapability	Description\fR
:PU=:	sequence received from the <PgUp> key
:PD=:	sequence received from the <PgDn> key
:HM=:	sequence received from the <Home> key
:EN=:	sequence received from the <End> key
:VB=:	sequence sent to start bold printing
:Vb=:	sequence sent to end bold printing
.in -0.25i
.SS "Author"
.PP
\fIElvis\fR was written by Steve Kirkendall.
He can be reached by email at: [e-mail]
for comments regarding \fIelvis\fR.