doc.sh

操作系统源代码

Xthe number of lines included in the range.
X.PP
XThe \fBf\fRile command tells you the name of the file,
Xwhether it has been modified,
Xthe number of lines in the file,
Xand the current line number.
XYou can also use it to change the name of the current file.
X.PP
XThe \fBso\fRurce command reads a sequence of colon mode commands from a file,
Xand interprets them.
X.PP
XThe \fB@\fR command executes the contents of a cut-buffer as EX commands.
X.PP
XThe \fBcol\fRor command only works under MS-DOS, or if you have an ANSI-compatible
Xcolor terminal.
XIt allows you to set the foreground and background colors
Xfor different types of text:
Xnormal, bold, italic, underlined, standout, pop-up menu, and visible selection.
XBy default, it changes the "normal" colors;
Xto change other colors, the first argument to the :color command should be
Xthe first letter of the type of text you want.
XThe syntax for the colors themselves is fairly intuitive.
XFor example, ":color light cyan on blue" causes normal text to be displayed
Xin light cyan on a blue background, and
X":color b bright white" causes bold text to be displayed in bright white on
Xa blue background.
XThe background color always defaults to the current background color of
Xnormal text.
XYour first :color command \fImust\fP specify both the foreground and background
Xfor normal text.
X.NH 2
XMultiple File Commands
X.if n .ul 0
X.ID
X.ps
Xargs [files]
Xnext[!] [files]
XNext[!]
Xprevious[!]
Xrewind[!]
X.DE
X.PP
XWhen you invoke \*E from your shell's command line,
Xany filenames that you give to \*E as arguments are stored in the args list.
XThe \fBar\fRgs command will display this list, or define a new one.
X.PP
XThe \fBn\fRext command switches from the current file to the next one
Xin the args list.
XYou may specify a new args list here, too.
X.PP
XThe \fBN\fRext and \fBpre\fRvious commands
X(they're really aliases for the same command)
Xswitch from the current file to the preceding file in the args list.
X.PP
XThe \fBrew\fRind command switches from the current file to the first file
Xin the args list.
X.NH 2
XSwitching Files
X.if n .ul 0
X.ID
X.ps
Xedit[!] [file]
Xtag[!] tagname
X.DE
X.PP
XThe \fBe\fRdit command allows to switch from the current file to some other file.
XThis has nothing to do with the args list, by the way.
X.PP
XThe \fBta\fRg command looks up a given tagname in a file called "tags".
XThis tells it which file the tag is in, and how to find it in that file.
X\*E then switches to the tag's file and finds the tag.
X.NH 2
XWorking with a Compiler
X.if n .ul 0
X.ID
X.ps
Xcc [files]
Xmake [target]
Xerrlist[!] [errlist]
X.DE
X.PP
XThe \fBcc\fR and \fBmak\fRe commands execute your compiler or "make" utility
Xand redirect any error messages into a file called "errlist".
XBy default, cc is run on the current file.
X(You should write it before running cc.)
XThe contents of the "errlist" file are then scanned for error messages.
XIf an error message is found, then the cursor is moved to the line where
Xthe error was detected,
Xand the description of the error is displayed on the status line.
X.PP
XAfter you've fixed one error, the \fBer\fRrlist command will move
Xthe cursor to the next error.
XIn visual command mode,
Xhitting `*' will do this, too.
X.PP
XYou can also create an "errlist" file from outside of \*E,
Xand use "\*E -m" to start elvis and have the cursor moved to the
Xfirst error.
XNote that you don't need to supply a filename with "\*E -m" because
Xthe error messages always say which source file an error is in.
X.PP
XNote:
XWhen you use errlist repeatedly to fix several errors in a single file,
Xit will attempt to adjust the reported line numbers to allow for lines
Xthat you have inserted or deleted.
XThese adjustments are made with the assumption that you will work though
Xthe file from the beginning to the end.
X.NH 2
XExit Commands
X.if n .ul 0
X.ID
X.ps
Xquit[!]
Xwq
Xxit
X.DE
X.PP
XThe \fBq\fRuit command exits from the editor without saving your file.
X.PP
XThe \fBwq\fR command writes your file out, then then exits.
X.PP
XThe \fBx\fRit command is similar to the \fBwq\fR command, except that
X\fBx\fRit won't bother to write your file if you haven't modified it.
X.NH 2
XFile I/O Commands
X.if n .ul 0
X.ID
X.ps
X[line] read file
X[line][,line] write[!] [[>>]file]
X.DE
X.PP
XThe \fBr\fRead command gets text from another file and inserts it
Xafter the specified line.
XIt can also read the output of a program;
Xsimply precede the program name by a '!' and use it in place of the file name.
X.PP
XThe \fBw\fRrite command writes the whole file, or just part of it,
Xto some other file.
XThe !, if present, will permit the lines to be written even if you've set
Xthe readonly option.
XIf you precede the filename by >> then the lines will be appended to the file.
XYou can send the lines to the standard input of a program by replacing the
Xfilename with a '!' followed by the command and its arguments.
X.PP
XNote: Be careful not to confuse ":w!filename" and ":w !command".
XTo write to a program, you must have at least one blank before the '!'.
X.NH 2
XDirectory Commands
X.if n .ul 0
X.ID
X.ps
Xcd [directory]
Xchdir [directory]
Xshell
X.DE
X.PP
XThe \fBcd\fR and \fBchd\fRir commands
X(really two names for one command)
Xswitch the current working directory.
X.PP
XThe \fBsh\fRell command starts an interactive shell.
X.NH 2
XDebugging Commands
X.if n .ul 0
X.ID
X.ps
X[line][,line] debug[!]
Xvalidate[!]
X.DE
X.PP
XThese commands are only available if you compile \*E with the -DDEBUG flag.
X.PP
XThe de\fBb\fRug command lists statistics for the blocks which contain
Xthe specified range of lines.
XIf the ! is present, then the contents of those blocks is displayed, too.
X.PP
XThe \fBva\fRlidate command checks certain variables for internal consistency.
XNormally it doesn't output anything unless it detects a problem.
XWith the !, though, it will always produce *some* output.
/
echo x - index.ms
sed '/^X/s///' > index.ms << '/'
X.XS 1
XINTRODUCTION
XWhat E\s-2LVIS\s+2 does,
XCopyright,
XHow to compile E\s-2LVIS\s+2,
XOverview
X.XA 2
XVISUAL MODE COMMANDS
XNormal interactive editing,
XInput mode,
XArrow keys,
XDigraphs,
XAbbreviations,
XAuto-indentation
X.XA 3
XCOLON MODE COMMANDS
XLine specifiers,
XText entry,
XCut & paste,
XDisplay text,
XGlobal operations,
XLine editing,
XUndo,
XConfiguration & status,
XMultiple files,
XSwitching files,
XWorking with a compiler,
XExiting,
XFile I/O,
XDirectory & shell,
XDebugging
X.XA 4
XREGULAR EXPRESSIONS
XSyntax,
XOptions,
XSubstitutions,
XExamples
X.XA 5
XOPTIONS
XAutoindent,
XAutoprint,
Xetc.
X.XA 6
XCUT BUFFERS
XPutting text into a cut buffer,
XPasting from a cut buffer,
XMacros,
XThe effect of switching files
X.XA 7
XDIFFERENCES BETWEEN E\s-2LVIS\s+2 AND THE REAL VI/EX
XExtensions,
XOmissions
X.XA 8
XINTERNAL
XFor programmers only,
XThe temporary file,
XImplementation of editing,
XMarks and the cursor,
XColon command interpretation,
XScreen control,
XPortability
X.XA 9
XCFLAGS
X.XA 10
XTERMCAP
X.XA 11
XENVIRONMENT VARIABLES
X.XA 12
XVERSIONS
X.XA 13
XQUESTIONS & ANSWERS
X.XE
X.PX
X.sp 0.3i
X.ce 1
XUNIX-style "man" pages appear at the end of this manual.
/
echo x - internal.ms
sed '/^X/s///' > internal.ms << '/'
X.Go 8 "INTERNAL"
X.PP
XYou don't need to know the material in this section to use \*E.
XYou only need it if you intend to modify \*E.
X.PP
XYou should also check out the CFLAGS, TERMCAP, ENVIRONMENT VARIABLES,
XVERSIONS, and QUIESTIONS & ANSWERS sections of this manual.
X.NH 2
XThe temporary file
X.PP
XThe temporary file is divided into blocks of 1024 bytes each.
XThe functions in "blk.c" maintain a cache of the five most recently used blocks,
Xto minimize file I/O.
X.PP
XWhen \*E starts up, the file is copied into the temporary file
Xby the function \fBtmpstart()\fR in "tmp.c".
XSmall amounts of extra space are inserted into the temporary file to
Xinsure that no text lines cross block boundaries.
XThis speeds up processing and simplifies storage management.
XThe extra space is filled with NUL characters.
Xthe input file must not contain any NULs, to avoid confusion.
XThis also limits lines to a length of 1023 characters or less.
X.PP
XThe data blocks aren't necessarily stored in sequence.
XFor example, it is entirely possible that the data block containing
Xthe first lines of text will be stored after the block containing the
Xlast lines of text.
X.PP
XIn RAM, \*E maintains two lists: one that describes the "proper"
Xorder of the disk blocks, and another that records the line number of
Xthe last line in each block.
XWhen \*E needs to fetch a given line of text, it uses these tables
Xto locate the data block which contains that line.
X.PP
XBefore each change is made to the file, these lists are copied.
XThe copies can be used to "undo" the change.
XAlso, the first list
X-- the one that lists the data blocks in their proper order --
Xis written to the first data block of the temp file.
XThis list can be used during file recovery.
X.PP
XWhen blocks are altered, they are rewritten to a \fIdifferent\fR block in the file,
Xand the order list is updated accordingly.
XThe original block is left intact, so that "undo" can be performed easily.
X\*E will eventually reclaim the original block, when it is no longer needed.
X.NH 2
XImplementation of Editing
X.PP
XThere are three basic operations which affect text:
X.ID
X\(bu delete text	- delete(from, to)
X\(bu add text	- add(at, text)
X\(bu yank text	- cut(from, to)
X.DE
X.PP
XTo yank text, all text between two text positions is copied into a cut buffer.
XThe original text is not changed.
XTo copy the text into a cut buffer,
Xyou need only remember which physical blocks that contain the cut text,
Xthe offset into the first block of the start of the cut,
Xthe offset into the last block of the end of the cut,
Xand what kind of cut it was.
X(Cuts may be either character cuts or line cuts;
Xthe kind of a cut affects the way it is later "put".)
XYanking is implemented in the function \fBcut()\fR,
Xand pasting is implemented in the function \fBpaste()\fR.
XThese functions are defined in "cut.c".
X.PP
XTo delete text, you must modify the first and last blocks, and
Xremove any reference to the intervening blocks in the header's list.
XThe text to be deleted is specified by two marks.
XThis is implemented in the function \fBdelete()\fR.
X.PP