For elvis, this means that edit sessions should be restartable. It is possible to begin an edit session with one elvis process, exit that process, and then later start a new elvis process which resumes the previous edit session.
To accomplish this, elvis stores its state in a file, called the session file. For all practical purposes, the session file is the session.
The name of the session file is stored in the session option. By default, this will be a file in your home directory, named "elvis*.ses", where "*" represents a number chosen at run-time to make the file name unique. You can specify some other name for the session file via the -ssession command-line flag.
If the session file doesn't already exist when elvis starts running, then elvis will create it.
When elvis exits, it will normally delete the session file if this is the elvis process that created it. If the session file was left over from some other elvis process, then elvis will not delete it upon exiting. This is controlled by the tempsession option; if you don't like elvis' default behavior then you can change it.
Elvis begins by initializing some options to hardcoded values.
Elvis then chooses which user interface it should use. Elvis does this by scanning the command line arguments for a -Ggui flag; if there is no such flag, then elvis tests each user interface and uses the best one that is expected to work. (For example, the "x11" interface is expected to work if there is a DISPLAY environment variable and the X server is accessible. If not, then the "x11" interface is rejected and some other interface is used.)
The session file is then opened or created. For preexisting session files, elvis scans the session file for any buffers in it, and adds them to its internal list. Elvis can even reload the "undo" versions of some buffers.
Elvis searches through the directories named in the elvispath option for a file named "elvis.ini". If it finds that file, then it loads it into a buffer named "Elvis initialization" and executes its contents as a series of ex commands. See section 10.2.1 for description of the default contents of this file.
After that, it attempts to similarly load some other files, but they aren't executed. Some of them will be executed later. These files are:
.-----------.----------------------.------------------------------. | FILE NAME | BUFFER NAME | PURPOSE | |-----------|----------------------|------------------------------| | elvis.msg | Elvis messages | used to translate messages | | elvis.brf | Elvis before reading | executed before loading file | | elvis.arf | Elvis after reading | executed after loading file | | elvis.bwf | Elvis before writing | executed before saving file | | elvis.awf | Elvis after writing | executed after saving file | ^-----------^----------------------^------------------------------^The "elvis.msg" file is described in section 11: Messages. The other files are described later in this section.
The next step in initialization is to load the first file and display it in a window. To do this, it first creates an empty buffer with the same name as the file. It then executes the "Elvis before reading" buffer (if it exists) on the empty buffer. The file's contents are then read into the buffer. Then the "Elvis after reading" buffer (if it exists) is executed on the new buffer. Finally, elvis creates a new window that shows the new buffer.
If the -a flag was given on the command line, then elvis will repeat the above steps for each file named on the command line. On the other hand, if no filenames were given on the command line then elvis will simply create a single untitled buffer and a window that shows it.
" DEFINE SOME DIGRAPHS
if os=="msdos" || os=="os2" || (os=="win32" && gui!="windows")
then source! (elvispath("elvis.pc8"))
else source! (elvispath("elvis.lat"))
This attempts to locate the "elvis.lat" or "elvis.pc8" file and execute it.
Those files contain ex scripts, consisting of a bunch of
:digraph commands that set up the
digraph table appropriately for the Latin-1 symbol set.
The "!" at the end of the :source
command name causes :source to silently ignore errors.
" CHOOSE SOME DEFAULT OPTION VALUES BASED ON THE INVOCATION NAME let p=tolower(basename(program)) if p == "ex" || p == "edit" then set! initialstate=ex if p == "view" then set! defaultreadonly if p == "edit" || p == "vedit" then set! novice if home == "" then let home=dirdir(program)These lines initialize certain options according to the name by which elvis was invoked. Traditionally, invoking vi by the name "ex" causes it to start up in ex mode instead of vi mode, and "view" causes the files to be treated as readonly.
" SYSTEM TWEAKS GO HERE
"
" The Linux console can't handle colors and underlining.
if gui=="termcap"
then {
if term=="linux"
then set! nottyunderline
}
This is an attempt to work around a bug in the Linux console driver.
The Linux console can't mix color attributes with the underline attribute.
" WINDOWS DEFAULT COLORS GO HERE (may be overridden in elvis.rc file)
if gui=="windows"
then {
color e green
color i magenta
color u blue
color f red
}
" X11 DEFAULT COLORS AND TOOLBAR GO HERE (may be overridden in .exrc file)
if gui=="x11"
then so! (elvispath("elvis.x11"))
These lines set the defaults for the "windows" and "x11" user interfaces.
Note that "x11" configuration commands are actually stored in a separate file. This is because there are large number of commands for setting up the toolbar, and I didn't want to force other GUIs to read them just to ignore them. You should set the defaults in "elvis.x11", and not in an app-defaults file. If you aren't using the "x11" user interface, then these lines have no effect.
" EXECUTE THE STANDARD CUSTOMIZATION SCRIPTS
let f=(os=="unix" ? ".elvisrc" : "elvis.rc")
if $EXINIT
then eval $EXINIT
else source! (exists("~"/f) ? "~"/f : "~/.exrc")
if exrc && getcwd()!=home
then safer! (exists(f) ? f : ".exrc")
set f=""
These lines set the f option to either ".elvisrc"
or "elvis.rc", whichever is appropriate for your operating system.
They then check whether an environment variable named "EXINIT" is set
to a non-empty value.
If so, then the value of EXINIT is executed as an ex command line;
otherwise the ".elvisrc" or "elvis.rc" file in your home directory is
executed, if it exists.
If that file doesn't exist, then it tries ".exrc"... which probably only makes
sense for Unix, but it is quicker to try & fail then to test before trying.
The "~" notation is UNIX's conventional alias for referring to files in your
home directory; elvis handles it correctly on non-UNIX systems too.
Note:
There is a hardcoded limit of (normally) 1023 characters for the result of
an expression. If your EXINIT environment variable's value is
longer than that, elvis won't be able to execute it.
If EXINIT or .elvisrc/elvis.rc/.exrc (whichever was executed) has set the exrc option then elvis will execute ".elvisrc" or "elvis.rc" in the current directory, if it exists; if not, then it tries ".exrc". Elvis uses :safer instead of :source to execute the file for security reasons.
" X11 INTERFACE DEFAULT FONTS GO HERE
if gui == "x11"
then if normalfont == ""
then {
set! normalfont="*-courier-medium-r-*-18-*"
set! boldfont="*-courier-bold-r-*-18-*"
set! italicfont="*-courier-medium-o-*-18-*"
}
These cause the x11 interface to use 18-point courier fonts, if you don't
explicitly name some other font on the command line
(-font fontname)
or by setting the normalfont option in your .exrc file.
" TAKE A GUESS AT THE BUFFER'S TYPE let! readeol=fileeol(filename)This line tries to guess whether the file is binary or not. This must be done before the file is loaded because for non-binary files elvis converts newlines to linefeeds as it reads the file.
" TAKE A GUESS AT THE BUFFER'S PREFERRED DISPLAY MODE
let e=tolower(dirext(filename))
if knownsyntax(filename)
then set! bufdisplay=syntax
if os=="unix" && buflines >= 1
then 1s/^#! *[^ ]*\/\([^ ]\+\).*/set! bufdisplay="syntax \1"/x
if !newfile
then {
if readeol=="binary" && bufdisplay=="normal"
then set! bufdisplay=hex
if e==".man"
then set! bufdisplay=man
if strlen(e)==2 && isnumber(e>>1) && buflines>=1
then 1s/^\./set! bufdisplay=man/x
if e==".tex"
then set! bufdisplay=tex
if e<<4==".htm"
then set! bufdisplay=html
if buflines >= 1 && bufdisplay=="hex"
then 1s/^<[HIThit!]/set! bufdisplay=html/x
if (filename<<5=="http:" || filename<<4=="ftp:")
&& strlen(e)<4 && bd=="hex"
then set! bufdisplay=normal
if bufdisplay=="normal" && buflines >= 1
then 1s/^From .*/set! bufdisplay="syntax email"/x
if dirdir(filename)=="/tmp" || dirdir(filename)=="/var/tmp"
then set! bufdisplay="syntax email"
}
These lines try to guess the preferred display mode for the file.
First it checks to see if the filename's extension is listed in the
elvis.syn file;
if so, then the s a string of digits |
| \0 | Insert a nul character |
| \a | Insert a bell character |
| \b | Insert a backspace character |
| \f | Insert a form-feed character |
| \n | Insert a line-feed character |
| \r | Insert a carriage-return character |
| \t | Insert a tab character |
^-------^----------------------------------------------------------^
These may be preceded by a backslash to force them to be treated normally.
The delimiting character can also be preceeded by a backslash to include
it in either the regular expression or the substitution string.
Traditionally \0 was a synonym for the &
symbol -- they both inserted a copy of the matching text.
Elvis breaks from tradition here to make \0 insert a NUL
character because there would otherwise be no way to have a substitution
insert a NUL character.
The first option is called "[no]magic". This is a boolean option, and it is "magic" (TRUE) by default. While in magic mode, all of the meta-characters behave as described above. In nomagic mode, the ., [...], and * characters loose their special meaning unless preceeded by a backslash. Also, in substitution text the & and ~ characters are treated literally unless preceeded by a backslash.
The second option is called "[no]ignorecase". This is a boolean option, and it is "noignorecase" (FALSE) by default. While in ignorecase mode, the searching mechanism will not distinguish between an uppercase letter and its lowercase form, except in a character list metacharacter. In noignorecase mode, uppercase and lowercase are treated as being different.
Also, the "[no]wrapscan" and "[no]autoselect" options affect searches.
:%s/utilize/use/gThis example deletes all whitespace that occurs at the end of a line anywhere in the file.
:%s/\s\+$//This example converts the current line to uppercase:
:s/.*/\U&/This example underlines each letter in the current line, by changing it into an "underscore backspace letter" sequence. (The ^H is entered as "control-V backspace".):
:s/[a-zA-Z]/_^H&/gThis example locates the last colon in a line, and swaps the text before the colon with the text after the colon. The first \( \) pair is used to delimit the stuff before the colon, and the second pair delimit the stuff after. In the substitution text, \1 and \2 are given in reverse order to perform the swap:
:s/\(.*\):\(.*\)/\2:\1/