elvis.9

操作系统设计与实现源码

The (j)oin  command  concatenates  all  lines  in  the  specified  range
together to form one big line.  If only a single line is specified, then
the following line is catenated onto it.

The ! command runs an external filter program, and feeds  the  specified
range of lines to it's stdin.  The lines are then replaced by the output
of the filter.  A typical example would be ':'a,'z!sort -n' to sort  the
lines 'a,'z according to their numeric values.

The < and > commands shift the specified range of lines left  or  right,
normally  by  the  width  of  1  tab character.  The 'shiftwidth' option
determines the shifting amount.

The (s)ubstitute command finds the regular expression in each line,  and


                                                                        



                                                                        


replaces it with the  replacement  text.   The  'p'  option  causes  the
altered lines to be printed, and the 'g' option permits all instances of
the regular expression to be found & replaced.  (Without 'g',  only  the
first occurrence is replaced.)



Undo



              undo

The (u)ndo command restores the file to the state it was in before  your
most recent command which changed text.



Configuration & Status



              map[!] [key mapped_to]
              unmap[!] key
              set [options]
              mkexrc
[line]        mark x
              visual
              version
[line][,line] =
              file

The (ma)p command allows  you  to  configure  elvis  to  recognize  your
function  keys,  and  treat  them  as though they transmitted some other
sequence of characters.  Normally this mapping is done only when in  the
visual command mode, but with the [!] present it will map keys under all
contexts.  When this command is given with no  arguments,  it  prints  a
table  showing  all  mappings currently in effect.  When called with two
arguments, the first is the  sequence  that  your  function  key  really
sends, and the second is the sequence that you want elvis to treat it as
having sent.

The (unm)ap command removes key definitions that were made via  the  map
command.

The (se)t command allows you examine or set various  options.   With  no
arguments,  it  displays  the  values of options that have been changed.
With the single argument 'all' it displays the values  of  all  options,
regardless  of  whether  they've been explicitly set or not.  Otherwise,
the arguments are treated as options to be set.


                                                                        



                                                                        


The (mk)exrc command saves the current configuration to  a  file  called
.exrc in the current directory.

The mar(k) command defines a named mark to refer to a specific place  in
the  file.   This  mark  may  be  used  later to specify lines for other
commands.

The (vi)sual command puts the  editor  into  visual  mode.   Instead  of
emulating ex, elvis will start emulating vi.

The (ve)rsion command tells you that what version of elvis this is.

The = command tells you what line you specified, or, if you specified  a
range  of lines, it will tell you both endpoints and the number of lines
included in the range.

The file command tells you the name of the file,  whether  it  has  been
modified, the number of lines in the file, and the current line number.


Multiple Files


              args [files]
              next[!] [files]
              Next[!]
              previous[!]
              rewind[!]

When you invoke elvis from your shell's command line, any filenames that
you  give to elvis as arguments are stored in the args list.  The (ar)gs
command will display this list, or define a new one.

The (n)ext command switches from the current file to the next one in the
args list.  You may specify a new args list here, too.

The (N)ext and (pre)vious commands (they're really aliases for the  same
command)  switch from the current file to the preceding file in the args
list.

The (rew)ind command switches from the current file to the first file in
the args list.



Switching Files






                                                                        



                                                                        


              edit[!] [file]
              tag[!] tagname

The (e)dit command allows to switch from the current file to some  other
file.  This has nothing to do with the args list, by the way.

The (ta)g command looks up a given tagname  in  a  file  called  'tags".
This tells it which file the tag is in, and how to find it in that file.
Elvis then switches to the tag's file and finds the tag.



Exiting



              quit[!]
              wq
              xit

The (q)uit command exits from the editor without saving your file.

The (wq) and (x)it commands (really two names for the same command) both
write the file before exiting.


File I/O


[line]        read file
[line][,line] write[!][[>>]file]

The (r)ead command gets text from another file and inserts it after  the
specified line.

The (w)rite command writes the whole file, or just part of it,  to  some
other file.  The !, if present, will permit the lines to be written even
if you've set the readonly option.  If you precede the  filename  by  >>
then the lies will be appended to the file.


Directory


              cd [directory]
              chdir [directory]
              shell

The (cd) and (chd)ir commands (really two names for one command)  switch
the current working directory.


                                                                        



                                                                        


The (sh)ell command starts an interactive shell.



Debugging



[line][,line] debug[!]
              validate[!]

These commands are only available if you compile elvis with the  -DDEBUG
flag.

The de(b)ug command  lists  stats  for  the  blocks  which  contain  the
specified  range  of  lines.   If the ! is present, then the contents of
those blocks is displayed, too.

The  (va)lidate  command   checks   certain   variables   for   internal
consistency.   Normally  it does not output anything unless it detects a
problem.  With the !, though, it will always produce *some* output.


Extensions


        In addition  to  the  standard  commands,  a  variety  of  extra
   features  are  present in elvis that are not present in vi.  They are
   described below.

.exrc
   Elvis first runs a .exrc file (if  there  is  one)  from  your  $HOME
   directory.  After  that,  it  runs a .exrc (if there is one) from the
   current directory.  The one in the  current  directory  may  override
   settings made by the one in the $HOME directory.

:mkexrc
:mk
   This EX command saves the current :set and :map configurations in the
   '.exrc' file in your current directory.

:args
:ar
   You can use the :args command to define a new args list, as in:

               :args *.h

   After you have defined a new args list, the next  time  you  issue  a
   :next command elvis will switch to the first file of the new list.



                                                                        



                                                                        


:Next
:previous
:N
:pre
   These commands move backwards through the args list.

zz
   In VI, the (lowercase) 'zz' command will center the current  line  on
   the screen, like 'z="

.
   The default count value for . is the same  as  the  previous  command
   which  .  is meant to repeat.  However, you can supply a new count if
   you wish. For example, after '3dw', '.' will delete 3 words, but '5.'
   will delete 5 words.

"
   The text which was most  recently  input  (via  a  'cw'  command,  or
   something  similar)  is  saved  in a cut buffer called ". (which is a
   pretty hard name to write in an English sentence).  You can use  this
   with the 'p' or 'P' commands thusly:

               ".p

K
   You can move the cursor onto a word and press shift-K to  have  elvis
   run  a reference program to look that word up.  This command alone is
   worth the price of admission!  See the ctags and ref programs.

input
   You can backspace back past the beginning of the line.  If  you  type
   CTRL-A, then the text that you input last time is inserted.  You will
   remain in input mode, so you can backspace over part of  it,  or  add
   more to it.  (This is sort of like CTRL-@ on the real vi, except that
   CTRL-A really works.)

   Real vi can only remember up to 128 characters of  input,  but  elvis
   can remember any amount.

:set charattr
:se ca
   Elvis can display 'backslash-f' style  character  attributes  on  the
   screen  as  you  edit.   The  following  example shows the recognized
   attributes:

               normal boldface italics

   NOTE: you must compile elvis without the  -DSET_NOCHARATTR  flag  for
   this to work.



                                                                        



                                                                        


Omissions

     A few vi features are missing.  The replace mode  is  a  hack.   It
does not save the text that it overwrites.

     Long lines are displayed differently----where  the  real  vi  would
wrap  a long line onto several rows of the screen, elvis simply displays
part of the line, and allows you to scroll the screen  sideways  to  see
the rest of it.

     The ':preserve' and ':recover' commands are missing, as is  the  -r
flag.    ':Preserve"   is  practically  never  used  and  since  use  of
':recover\*(CQ is so rare, it was decided to implement it as a  separate
program.   There's  no  need to load the recovery code into memory every
time you edit a file.

     LISP support is missing.  The '@' and ':@'  commands  are  missing.
You cannot APPEND to a cut buffer.

Options

     A variety of options can be set as described below:

   Name      Abbr  Type     Default    Description
   autoindent as   Bool     FALSE      autoindent during input?
   autowrite aw    Bool     FALSE      write file for :n command?
   charattr  ca    Bool     FALSE      display bold & underline chars?
   columns   co    Number   80         width of screen, in characters
   directory dir   String   /usr/tmp   where tmp files are kept
   errorbells eb   Bool     TRUE       ring bell on error?
   exrefresh er    Bool     TRUE       EX mode calls write() often?
   ignorecase ic   Bool     FALSE      searches: upper/lowercase OK?
   keytime   kt    Number   1          allow slow receipt of ESC seq?
   keywordprg kp   String   /usr/bin/ref program to run for shift-K
   lines     ln    Number   25         height of screen, in lines
   list      li    Bool     FALSE      show tabs as '^I'?
   magic     ma    Bool     TRUE       searches: allow metacharacters?
   paragraphs pa   String   PPppPApa   paragraphs start with .PP, etc.
   readonly  ro    Bool     FALSE      no file should be written back?
   report    re    Number   5          report changes to X lines?
   scroll    sc    Number   12         default #lines for ^U and ^D
   sections  se    String   SEseSHsh   sections start with .SE, etc.
   shell     sh    String   /bin/sh    shell program, from environment
   shiftwidth sw   Number   8          width of < or > commands
   sidescroll ss   Number   8          #chars to scroll sideways by
   sync      sy    Bool     FALSE      call sync() after each change?
   tabstop   ts    Number   8          width of a tab character
   term      te    String   "?"        terminal type, from environment
   vbell     vb    Bool     TRUE       use visible bell if possible?
   warn      wa    Bool     TRUE       warn if file not saved for :!cmd


                                                                        



                                                                        


   wrapmargin wm   Number   0          Insert newline after which col?
   wrapscan  ws    Bool     TRUE       searches: wrap at EOF?

autoindent
   During input mode, the autoindent option will cause each  added  line
   to begin with the same amount of leading whitespace as the line above
   it.  Without autoindent, added lines are initially empty.

autowrite
   When you're editing one file and decide to switch  to  another----via
   the  :tag  command, or :next command, perhaps----if your current file
   has been modified, then elvis will normally print  an  error  message
   and refuse to switch.

   However, if the autowrite option is on, then  elvis  will  write  the
   modified  version  of the current file and successfully switch to the