ex-vi/ex.1

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.\"	from ex.1	6.4.1 (2.11BSD) 1996/10/21
.\"
.\"	Sccsid @(#)ex.1	1.44 (gritter) 12/1/04
.\"
.ie \n(.g==1 \{\
.ds lq \(lq
.ds rq \(rq
.\}
.el \{\
.ds lq ``
.ds rq ''
.\}
.TH EX 1 "12/1/04" "Ancient Unix Ports" "User Commands"
.SH NAME
ex, edit \- text editor
.SH SYNOPSIS
.HP
.ad l
\fBex\fR [\fB\-c\fI\ command\fR|\fB+\fIcommand\fR]
[\fB\-r\fR\ [\fIfilename\fR]] [\fB\-s\fR|\fB\-\fR]
[\fB\-t\fI\ tagstring\fR] [\fB\-w\fI\ size\fR]
[\fB\-lLRvV\fR] [\fIfile\fR ...]
.HP
.ad l
\fBedit\fR [\fB\-c\fI\ command\fR|\fB+\fIcommand\fR]
[\fB\-r\fR\ [\fIfilename\fR]] [\fB\-s\fR|\fB\-\fR]
[\fB\-t\fI\ tagstring\fR] [\fB\-w\fI\ size\fR]
[\fB\-lLRvV\fR] [\fIfile\fR ...]
.br
.ad b
.SH DESCRIPTION
.I Ex
is the root of a family of editors:
.I edit,
.I ex
and
.I vi.
.I Ex
is a superset of
.I ed,
with the most notable extension being a display editing facility.
Display based editing on
.SM CRT
terminals is the focus of
.IR vi .
.PP
For those who have not used
.I ed,
or for casual users, the editor
.I edit
may be convenient.
It avoids some of the complexities of
.I ex
used mostly by systems programmers and persons very familiar with
.I ed.
.PP
The following options are accepted:
.TP
\fB\-c\fP\fI\ command\fP or \fB+\fP\fIcommand\fP
Execute
.I command
when editing begins.
.TP
.B \-l
Start in a special mode useful for the
.I Lisp
programming language.
.TP
\fB\-r\fI\ [filename]\fR or \fB\-L\fR
When no argument is supplied with this option,
all files to be recovered are listed
and the editor exits immediately.
If a
.I filename
is specified,
the corresponding temporary file is opened in recovery mode.
.TP
.B \-R
Files are opened read-only when this option is given.
.TP
.BR \-s \ or\  \-
Script mode;
all feedback for interactive editing is disabled.
.SM EXINIT
and
.I .exrc
files are not processed.
.TP
.BI \-t \ tagstring
Read the
.I tags
file,
then choose the file and position specified by
.I tagstring
for editing.
.TP
.B \-v
Start in visual mode even if called as
.IR ex .
.TP
.B \-V
Echo command input to standard error,
unless it originates from a terminal.
.TP
.BI \-w \ size
Specify the size of the editing window for visual mode.
.\"	from ex.rm       8.1 (Berkeley) 6/8/93
.SS "File manipulation"
.I Ex
is normally editing the contents of a single file,
whose name is recorded in the
.I current
file name.
.I Ex
performs all editing actions in a buffer
(actually a temporary file)
into which the text of the file is initially read.
Changes made to the buffer have no effect on the file being
edited unless and until the buffer contents are written out to the
file with a
.I write
command.
After the buffer contents are written,
the previous contents of the written file are no longer accessible.
When a file is edited,
its name becomes the current file name,
and its contents are read into the buffer.
.PP
The current file is almost always considered to be
.I edited.
This means that the contents of the buffer are logically
connected with the current file name,
so that writing the current buffer contents onto that file,
even if it exists,
is a reasonable action.
If the current file is not 
.I edited
then
.I ex
will not normally write on it if it already exists.
.PP
For saving blocks of text while editing, and especially when editing
more than one file,
.I ex
has a group of named buffers.
These are similar to the normal buffer, except that only a limited number
of operations are available on them.
The buffers have names
.I a
through
.I z.
.SS "Exceptional Conditions"
.PP
When errors occur
.I ex
(optionally) rings the terminal bell and, in any case, prints an error
diagnostic.  If the primary input is from a file, editor processing
will terminate.  If an interrupt signal is received,
.I ex
prints \*(lqInterrupt\*(rq and returns to its command level.  If the primary
input is a file, then
.I ex
will exit when this occurs.
.PP
If a hangup signal is received and the buffer has been modified since
it was last written out, or if the system crashes, either the editor
(in the first case) or the system (after it reboots in the second) will
attempt to preserve the buffer.  The next time the user logs in he should be
able to recover the work he was doing, losing at most a few lines of
changes from the last point before the hangup or editor crash.  To
recover a file one can use the
.B \-r
option.  If one was editing the file
.I resume,
then he should change
to the directory where he were when the crash occurred, giving the command
.RS
.sp
\fBex \-r\fP\fI resume\fP
.sp
.RE
After checking that the retrieved file is indeed ok, he can
.I write
it over the previous contents of that file.
.PP
The user will normally get mail from the system telling him when a file has
been saved after a crash.  The command
.RS
.sp
\fBex\fP \-\fBr\fP
.sp
.RE 
will print a list of the files which have been saved for the user. 
.\"(In the case of a hangup,
.\"the file will not appear in the list,
.\"although it can be recovered.)
.SS "Editing modes"
.PP
.I Ex
has five distinct modes.  The primary mode is
.I command
mode.  Commands are entered in command mode when a `:' prompt is
present, and are executed each time a complete line is sent.  In
.I "text input"
mode
.I ex
gathers input lines and places them in the file.  The
.I append,
.I insert,
and
.I change
commands use text input mode.
No prompt is printed when in text input mode.
This mode is left by typing a `.' alone at the beginning of a line, and
.I command
mode resumes.
.PP
The last three modes are
.I open
and
.I visual
modes, entered by the commands of the same name, and, within open and
visual modes
.I "text insertion"
mode.
.I Open
and
.I visual
modes allow local editing operations to be performed on the text in the
file.  The
.I open
command displays one line at a time on any terminal while
.I visual
works on 
.SM CRT
terminals with random positioning cursors, using the
screen as a (single) window for file editing changes.
These modes are described (only) in
.I "An Introduction to Display Editing with Vi."
.SS "Command structure"
.PP
Most command names are English words,
and initial prefixes of the words are acceptable abbreviations.
The ambiguity of abbreviations is resolved in favor of the more commonly
used commands.
.PP
Most commands accept prefix addresses specifying the lines in the file
upon which they are to have effect.
The forms of these addresses will be discussed below.
A number of commands also may take a trailing
.I count
specifying the number of lines to be involved in the command.
Thus the command \*(lq10p\*(rq will print the tenth line in the buffer while
\*(lqdelete 5\*(rq will delete five lines from the buffer,
starting with the current line.
.PP
Some commands take other information or parameters,
this information always being given after the command name.
.PP
A number of commands have two distinct variants.
The variant form of the command is invoked by placing an
`!' immediately after the command name. 
Some of the default variants may be controlled by options;
in this case, the `!' serves to toggle the default.
.PP
The characters `#', `p' and `l' may be placed after many commands
(A `p' or `l' must be preceded by a blank or tab
except in the single special case `dp').
In this case, the command abbreviated by these characters
is executed after the command completes.
Since
.I ex
normally prints the new current line after each change, `p' is rarely necessary.
Any number of `+' or `\-' characters may also be given with these flags.
If they appear, the specified offset is applied to the current line
value before the printing command is executed.
.PP
It is possible to give editor commands which are ignored.
This is useful when making complex editor scripts
for which comments are desired.
The comment character is the double quote: ".
Any command line beginning with " is ignored.
Comments beginning with " may also be placed at the ends
of commands, except in cases where they could be confused as part
of text (shell escapes and the substitute and map commands).
.PP
More than one command may be placed on a line by separating each pair
of commands by a `|' character.
However the
.I global
commands,
comments,
and the shell escape `!'
must be the last command on a line, as they are not terminated by a `|'.
.SS "Command addressing"
.IP \fB.\fR 20
The current line.
Most commands leave the current line as the last line which they affect.
The default address for most commands is the current line,
thus `\fB.\fR' is rarely used alone as an address.
.IP \fIn\fR 20
The \fIn\fRth line in the editor's buffer, lines being numbered
sequentially from 1.
.IP \fB$\fR 20
The last line in the buffer.
.IP \fB%\fR 20
An abbreviation for \*(lq1,$\*(rq, the entire buffer.
.IP \fI+n\fR\ \fI\-n\fR 20
An offset relative to the current buffer line.
The forms `.+3' `+3' and `+++' are all equivalent;
if the current line is line 100 they all address line 103.
.IP \fB/\fIpat\fR\fB/\fR\ \fB?\fIpat\fR\fB?\fR 20
Scan forward and backward respectively for a line containing \fIpat\fR, a
regular expression (as defined below).  The scans normally wrap around the end
of the buffer.
If all that is desired is to print the next line containing \fIpat\fR, then
the trailing \fB/\fR or \fB?\fR may be omitted.
If \fIpat\fP is omitted or explicitly empty, then the last
regular expression specified is located.
The forms \fB\e/\fP and \fB\e?\fP scan
using the last regular expression used in a scan; after a substitute
\fB//\fP and \fB??\fP would scan using the substitute's regular expression.
.IP \fB\(aa\(aa\fP\ \fB\(aa\fP\fIx\fP 20
Before each non-relative motion of the current line `\fB.\fP',
the previous current line is marked with a tag, subsequently referred to as
`\(aa\(aa'.
This makes it easy to refer or return to this previous context.
Marks may also be established by the
.I mark
command, using single lower case letters
.I x
and the marked lines referred to as
`\(aa\fIx\fR'.
.PP
Addresses to commands consist of a series of addressing primitives,
separated by `,' or `;'.
Such address lists are evaluated left-to-right.
When addresses are separated by `;' the current line `\fB.\fR'
is set to the value of the previous addressing expression
before the next address is interpreted.
If more addresses are given than the command requires,
then all but the last one or two are ignored.
If the command takes two addresses, the first addressed line must
precede the second in the buffer.
.PP
Null address specifications are permitted in a list of addresses,
the default in this case is the current line `.';
thus `,100' is equivalent to `\fB.\fR,100'.
It is an error to give a prefix address to a command which expects none.
.SS "Command descriptions"
.PP
The following form is a prototype for all
.I ex
commands:
.RS
.sp
\fIaddress\fR \fBcommand\fR \fI! parameters count flags\fR
.sp
.RE
All parts are optional; the degenerate case is the empty command which prints
the next line in the file.  For sanity with use from within
.I visual
mode,
.I ex
ignores a \*(lq:\*(rq preceding any command.
.PP
In the following command descriptions, the
default addresses are shown in parentheses,
which are
.I not,
however,
part of the command.
.TP
\fBabbreviate\fR \fIword rhs\fP	abbr: \fBab\fP
Add the named abbreviation to the current list.
When in input mode in visual, if
.I word
is typed as a complete word, it will be changed to
.I rhs .
.LP
( \fB.\fR ) \fBappend\fR	abbr: \fBa\fR
.br
\fItext\fR
.br
\&\fB.\fR
.RS
Reads the input text and places it after the specified line.
After the command, `\fB.\fR'
addresses the last line input or the
specified line if no lines were input.
If address `0' is given,
text is placed at the beginning of the buffer.
.RE
.LP
\fBa!\fR
.br
\fItext\fR
.br
\&\fB.\fR
.RS
The variant flag to
.I append
toggles the setting for the
.I autoindent
option during the input of
.I text.
.RE
.TP
\fBargs\fR
The members of the argument list are printed, with the current argument
delimited by `[' and `]'.
.TP
\fBcd\fR \fIdirectory\fR
The
.I cd
command is a synonym for
.I chdir.
.LP
( \fB.\fP , \fB.\fP ) \fBchange\fP \fIcount\fP	abbr: \fBc\fP
.br
\fItext\fP
.br
\&\fB.\fP
.RS
Replaces the specified lines with the input \fItext\fP.
The current line becomes the last line input;
if no lines were input it is left as for a
\fIdelete\fP.
.RE
.LP
\fBc!\fP
.br
\fItext\fP
.br
\&\fB.\fP
.RS
The variant toggles
.I autoindent
during the
.I change.
.RE
.TP
\fBchdir\fR \fIdirectory\fR
The specified \fIdirectory\fR becomes the current directory.
If no directory is specified, the current value of the
.I home
option is used as the target directory.
After a
.I chdir
the current file is not considered to have been
edited so that write restrictions on pre-existing files apply.
.TP
( \fB.\fP , \fB.\fP )\|\fBcopy\fP \fIaddr\fP \fIflags\fP	abbr: \fBco\fP
A \fIcopy\fP
of the specified lines is placed after
.I addr,
which may be `0'.
The current line
`\fB.\fR'
addresses the last line of the copy.
The command
.I t
is a synonym for
.I copy.
.TP
( \fB.\fR , \fB.\fR )\|\fBdelete\fR \fIbuffer\fR \fIcount\fR \fIflags\fR	abbr: \fBd\fR
Removes the specified lines from the buffer.
The line after the last line deleted becomes the current line;
if the lines deleted were originally at the end,
the new last line becomes the current line.
If a named
.I buffer
is specified by giving a letter,
then the specified lines are saved in that buffer,
or appended to it if an upper case letter is used.
.LP
\fBedit\fR \fIfile\fR	abbr: \fBe\fR
.br
\fBex\fR \fIfile\fR
.RS
Used to begin an editing session on a new file.
The editor
first checks to see if the buffer has been modified since the last
.I write
command was issued.
If it has been,
a warning is issued and the
command is aborted.
The
command otherwise deletes the entire contents of the editor buffer,
makes the named file the current file and prints the new filename.
After insuring that this file is sensible
(i.e., that it is not a binary file such as a directory,
a block or character special file other than
.I /dev/tty,
a terminal,
or a binary or executable file),
the editor reads the file into its buffer.
.PP
If the read of the file completes without error,
the number of lines and characters read is typed.
Any null characters in the file are discarded.
If none of these errors occurred, the file is considered
.I edited.
If the last line of the input file is missing the trailing
newline character, it will be supplied and a complaint will be issued.
This command leaves the current line `\fB.\fR' at the last line read.
If executed from within
.I open
or
.I visual,
the current line is initially the first line of the file.
.RE
.TP
\fBe!\fR \fIfile\fR
The variant form suppresses the complaint about modifications having
been made and not written from the editor buffer, thus
discarding all changes which have been made before editing the new file.
.TP
\fBe\fR \fB+\fIn\fR \fIfile\fR
Causes the editor to begin at line
.I n
rather than at the last line;
\fIn\fR may also be an editor command containing no spaces,
e.g.: \*(lq+/pat\*(rq.
.TP
\fBfile\fR	abbr: \fBf\fR
Prints the current file name,
whether it has been `[Modified]' since the last
.I write 
command,
whether it is
.I "read only" ,
the current line,
the number of lines in the buffer,
and the percentage of the way through the buffer of the current line.
In the rare case that the current file is `[Not edited]' this is
noted also; in this case one has to use the form \fBw!\fR to write to
the file, since the editor is not sure that a \fBwrite\fR will not
destroy a file unrelated to the current contents of the buffer.
.TP
\fBfile\fR \fIfile\fR
The current file name is changed to
.I file
which is considered 
`[Not edited]'.
.TP
( 1 , $ ) \fBglobal\fR /\fIpat\|\fR/ \fIcmds\fR	abbr: \fBg\fR
First marks each line among those specified which matches
the given regular expression.
Then the given command list is executed with `\fB.\fR' initially
set to each marked line.
.IP
The command list consists of the remaining commands on the current
input line and may continue to multiple lines by ending all but the
last such line with a `\e'.
If
.I cmds
(and possibly the trailing \fB/\fR delimiter) is omitted, each line matching
.I pat
is printed.
.I Append,
.I insert,
and
.I change
commands and associated input are permitted;
the `\fB.\fR' terminating input may be omitted if it would be on the
last line of the command list.
.I Open
and
.I visual
commands are permitted in the command list and take input from the terminal.
.IP
The
.I global
command itself may not appear in
.I cmds.
The
.I undo
command is also not permitted there,
as
.I undo
instead can be used to reverse the entire
.I global
command.
The options
.I autoprint
and
.I autoindent
are inhibited during a
.I global,
(and possibly the trailing \fB/\fR delimiter) and the value of the
.I report
option is temporarily infinite,
in deference to a \fIreport\fR for the entire global.
Finally, the context mark `\'\'' is set to the value of
`.' before the global command begins and is not changed during a global
command,
except perhaps by an
.I open
or
.I visual
within the
.I global.
.TP
\fBg!\fR \fB/\fIpat\fB/\fR \fIcmds\fR	abbr: \fBv\fR
The variant form of \fIglobal\fR runs \fIcmds\fR at each line not matching
\fIpat\fR.
.LP
( \fB.\fR )\|\fBinsert\fR	abbr: \fBi\fR
.br
\fItext\fR
.br
\&\fB.\fR
.RS
Places the given text before the specified line.
The current line is left at the last line input;
if there were none input it is left at the line before the addressed line.
This command differs from
.I append
only in the placement of text.
.RE
.LP
\fBi!\fR
.br
\fItext\fR
.br
\&\fB.\fR
.RS
The variant toggles
.I autoindent
during the
.I insert.
.RE
.TP
( \fB.\fR , \fB.\fR+1 ) \fBjoin\fR \fIcount\fR \fIflags\fR	abbr: \fBj\fR
Places the text from a specified range of lines
together on one line.
White space is adjusted at each junction to provide at least
one blank character, two if there was a `\fB.\fR' at the end of the line,
or none if the first following character is a `)'.
If there is already white space at the end of the line,
then the white space at the start of the next line will be discarded.
.TP
\fBj!\fR
The variant causes a simpler
.I join
with no white space processing; the characters in the lines are simply
concatenated.
.TP
( \fB.\fR ) \fBk\fR \fIx\fR
The
.I k
command is a synonym for
.I mark.
It does not require a blank or tab before the following letter.
.TP
( \fB.\fR , \fB.\fR ) \fBlist\fR \fIcount\fR \fIflags\fR
Prints the specified lines in a more unambiguous way:
tabs are printed as `^I'
and the end of each line is marked with a trailing `$'.
The current line is left at the last line printed.
.TP
\fBmap\fR[\fB!\fR] \fIlhs\fR \fIrhs\fR
The
.I map
command is used to define macros for use in
.I visual
command mode.
.I Lhs
should be a single character, or the sequence \*(lq#n\*(rq, for n a digit,
referring to function key \fIn\fR.  When this character or function key
is typed in
.I visual
mode, it will be as though the corresponding \fIrhs\fR had been typed.
On terminals without function keys, the user can type \*(lq#n\*(rq.
If the `\fB!\fP' character follows the command name,
the mapping is interpreted in input mode.
See section 6.9 of the \*(lqIntroduction to Display Editing with Vi\*(rq
for more details.
.TP
( \fB.\fR ) \fBmark\fR \fIx\fR
Gives the specified line mark
.I x,
a single lower case letter.
The
.I x
must be preceded by a blank or a tab.
The addressing form `\'x' then addresses this line.
The current line is not affected by this command.
.TP
( \fB.\fR , \fB.\fR ) \fBmove\fR \fIaddr\fR	abbr: \fBm\fR
The
.I move
command repositions the specified lines to be after
.I addr .
The first of the moved lines becomes the current line.
.TP
\fBnext\fR	abbr: \fBn\fR
The next file from the command line argument list is edited.
.TP
\fBn!\fR
The variant suppresses warnings about the modifications to the buffer not
having been written out, discarding (irretrievably) any changes which may
have been made.
.LP
\fBn\fR \fIfilelist\fR
.br
\fBn\fR \fB+\fIcommand\fR \fIfilelist\fR
.RS
The specified
.I filelist
is expanded and the resulting list replaces the
current argument list;
the first file in the new list is then edited.
If
.I command
is given (it must contain no spaces), then it is executed after editing the first such file.
.RE
.TP
( \fB.\fR , \fB.\fR ) \fBnumber\fR \fIcount\fR \fIflags\fR	abbr: \fB#\fR or \fBnu\fR
Prints each specified line preceded by its buffer line
number.
The current line is left at the last line printed.
.LP
( \fB.\fR ) \fBopen\fR \fIflags\fR	abbr: \fBo\fR
.br
( \fB.\fR ) \fBopen\fR /\fIpat\|\fR/ \fIflags\fR
.RS
Enters intraline editing \fIopen\fR mode at each addressed line.
If
.I pat
is given,
then the cursor will be placed initially at the beginning of the
string matched by the pattern.
To exit this mode use Q.
See
.I "An Introduction to Display Editing with Vi"
for more details.
.RE
.TP
\fBpreserve\fR
The current editor buffer is saved as though the system had just crashed.
This command is for use only in emergencies when a
.I write
command has resulted in an error.
.TP
( \fB.\fR , \fB.\fR )\|\fBprint\fR \fIcount\fR	abbr: \fBp\fR or \fBP\fR
Prints the specified lines
with non-printing characters printed as control characters `^\fIx\fR\|';
delete (octal 177) is represented as `^?'.
The current line is left at the last line printed.
.TP
( \fB.\fR )\|\fBput\fR \fIbuffer\fR	abbr: \fBpu\fR
Puts back
previously
.I deleted
or
.I yanked
lines.
Normally used with
.I delete
to effect movement of lines,
or with
.I yank
to effect duplication of lines.
If no
.I buffer
is specified, then the last
.I deleted
or
.I yanked
text is restored.
But no modifying commands may intervene between the
.I delete
or
.I yank
and the
.I put,
nor may lines be moved between files without using a named buffer.
By using a named buffer, text may be restored that was saved there at any
previous time.
.TP
\fBquit\fR	abbr: \fBq\fR
Causes 
.I ex
to terminate.
No automatic write of the editor buffer to a file is performed.
However,
.I ex
issues a warning message if the file has changed
since the last
.I write
command was issued, and does not
.I quit.
\fIEx\fR
will also issue a diagnostic if there are more files in the argument
list.
.FE
Normally, the user will wish to save his changes, and he
should give a \fIwrite\fR command;
if he wishes to discard them, he should the \fBq!\fR command variant.
.TP
\fBq!\fR
Quits from the editor, discarding changes to the buffer without complaint.
.TP
( \fB.\fR ) \fBread\fR \fIfile\fR	abbr: \fBr\fR
Places a copy of the text of the given file in the
editing buffer after the specified line.
If no 
.I file
is given the current file name is used.
The current file name is not changed unless there is none in which
case
.I file
becomes the current name.
The sensibility restrictions for the 
.I edit
command apply here also.
If the file buffer is empty and there is no current name then
.I ex
treats this as an
.I edit
command.
.IP
Address `0' is legal for this command and causes the file to be read at
the beginning of the buffer.
Statistics are given as for the 
.I edit
command when the 
.I read
successfully terminates.
After a
.I read
the current line is the last line read.
Within
.I open
and
.I visual
the current line is set to the first line read rather than the last.
.TP
( \fB.\fR ) \fBread\fR  \fB!\fR\fIcommand\fR
Reads the output of the command
.I command
into the buffer after the specified line.
This is not a variant form of the command, rather a read
specifying a
.I command
rather than a 
.I filename;
a blank or tab before the \fB!\fR is mandatory.
.TP
\fBrecover \fIfile\fR
Recovers
.I file
from the system save area.
Used after a accidental hangup of the phone
or a system crash or
.I preserve
command.
Except when
.I preserve
is used, the user will be notified by mail when a file is saved.
.TP
\fBrewind\fR	abbr: \fBrew\fR
The argument list is rewound, and the first file in the list is edited.
.TP
\fBrew!\fR
Rewinds the argument list discarding any changes made to the current buffer.
.TP
\fBset\fR \fIparameter\fR
With no arguments, prints those options whose values have been
changed from their defaults;
with parameter
.I all
it prints all of the option values.
.IP
Giving an option name followed by a `?'
causes the current value of that option to be printed.
The `?' is unnecessary unless the option is Boolean valued.
Boolean options are given values either by the form
`set \fIoption\fR' to turn them on or
`set no\fIoption\fR' to turn them off;
string and numeric options are assigned via the form
`set \fIoption\fR=value'.
.IP
More than one parameter may be given to 
.I set \|;
they are interpreted left-to-right.
.IP
A list of options can be found below.
.TP
\fBshell\fR	abbr: \fBsh\fR
A new shell is created.
When it terminates, editing resumes.
.TP
\fBsource\fR \fIfile\fR	abbr: \fBso\fR
Reads and executes commands from the specified file.
.I Source
commands may be nested.
.LP
.ad l
(\ \fB.\fR\ ,\ \fB.\fR\ )\ \fBsubstitute\fR\ /\fIpat\fR\|/\fIrepl\fR\|/\ \fIoptions\fR\ \fIcount\fR\ \fIflags\fR
.RS
abbr: \fBs\fR
.br
.ad b
On each specified line, the first instance of pattern
.I pat
is replaced by replacement pattern
.I repl.
If the
.I global
indicator option character `g'
appears, then all instances are substituted;
if the
.I confirm
indication character `c' appears,
then before each substitution the line to be substituted
is typed with the string to be substituted marked
with `^' characters.
By typing an `y' one can cause the substitution to be performed,
any other input causes no change to take place.
After a
.I substitute
the current line is the last line substituted.
.PP
Lines may be split by substituting
new-line characters into them.
The newline in
.I repl
must be escaped by preceding it with a `\e'.
Other metacharacters available in
.I pat
and
.I repl
are described below.
.RE
.TP
.B stop
Suspends the editor, returning control to the top level shell.
If
.I autowrite
is set and there are unsaved changes,
a write is done first unless the form
.B stop !
is used.
This commands is only available where supported by the teletype driver,
shell and operating system.
.TP
( \fB.\fR , \fB.\fR ) \fBsubstitute\fR \fIoptions\fR \fIcount\fR \fIflags\fR	abbr: \fBs\fR
If
.I pat
and
.I repl
are omitted, then the last substitution is repeated.
This is a synonym for the
.B &
command.
.TP
( \fB.\fR , \fB.\fR ) \fBt\fR \fIaddr\fR \fIflags\fR
The
.I t
command is a synonym for 
.I copy .
.TP
\fBta\fR \fItag\fR
The focus of editing switches to the location of
.I tag,
switching to a different line in the current file where it is defined,
or if necessary to another file.
.IP
The tags file is normally created by a program such as
.I ctags,
and consists of a number of lines with three fields separated by blanks
or tabs.  The first field gives the name of the tag,
the second the name of the file where the tag resides, and the third
gives an addressing form which can be used by the editor to find the tag;
this field is usually a contextual scan using `/\fIpat\fR/' to be immune
to minor changes in the file.  Such scans are always performed as if
.I nomagic
was set.
.IP
The tag names in the tags file must be sorted alphabetically.
.TP
\fBunabbreviate\fR \fIword\fP	abbr: \fBuna\fP
Delete
.I word
from the list of abbreviations.
.TP
\fBundo\fR	abbr: \fBu\fR
Reverses the changes made in the buffer by the last
buffer editing command.
Note that
.I global
commands are considered a single command for the purpose of 
.I undo
(as are
.I open
and
.I visual.)
Also, the commands
.I write
and
.I edit
which interact with the
file system cannot be undone.
.I Undo
is its own inverse.
.IP
.I Undo
always marks the previous value of the current line `\fB.\fR'
as `\'\''.
After an
.I undo
the current line is the first line restored
or the line before the first line deleted if no lines were restored.
For commands with more global effect
such as
.I global
and
.I visual
the current line regains it's pre-command value after an
.I undo.
.TP
\fBunmap\fR[\fB!\fR] \fIlhs\fR
The macro expansion associated by
.I map
for
.I lhs
is removed.
.TP
( 1 , $ ) \fBv\fR /\fIpat\fR\|/ \fIcmds\fR
A synonym for the
.I global
command variant \fBg!\fR, running the specified \fIcmds\fR on each
line which does not match \fIpat\fR.
.TP
\fBversion\fR	abbr: \fBve\fR
Prints the current version number of the editor
as well as the date the editor was last changed.
.TP
( \fB.\fR ) \fBvisual\fR \fItype\fR \fIcount\fR \fIflags\fR	abbr: \fBvi\fR
Enters visual mode at the specified line.
.I Type
is optional and may be `\-' , `^' or `\fB.\fR'
as in the
.I z
command to specify the placement of the specified line on the screen.
By default, if
.I type
is omitted, the specified line is placed as the first on the screen.
A
.I count
specifies an initial window size; the default is the value of the option
.I window.
See the document
.I "An Introduction to Display Editing with Vi"
for more details.
To exit this mode, type Q.
.LP
\fBvisual\fP file
.br
\fBvisual\fP +\fIn\fP file
.RS
From visual mode,
this command is the same as edit.
.RE
.TP
( 1 , $ ) \fBwrite\fR \fIfile\fR	abbr: \fBw\fR
Writes changes made back to \fIfile\fR, printing the number of lines and
characters written.
Normally \fIfile\fR is omitted and the text goes back where it came from.
If a \fIfile\fR is specified, then text will be written to that file.
If the file does not exist it is created.
The current file name is changed only if there is no current file
name; the current line is never changed.
.IP
If an error occurs while writing the current and
.I edited
file, the editor
considers that there has been \*(lqNo write since last change\*(rq
even if the buffer had not previously been modified.
.TP
( 1 , $ ) \fBwrite>>\fR \fIfile\fR	abbr: \fBw>>\fR
Writes the buffer contents at the end of
an existing file.
.IP
.TP
\fBw!\fR \fIname\fR
Overrides the checking of the normal \fIwrite\fR command,
and will write to any file which the system permits.
.TP
( 1 , $ ) \fBw\fR  \fB!\fR\fIcommand\fR
Writes the specified lines into 
.I command.
Note the difference between \fBw!\fR which overrides checks and
\fBw\ \ !\fR which writes to a command.
.TP
\fBwq\fR \fIname\fR
Like a \fIwrite\fR and then a \fIquit\fR command.
.TP
\fBwq!\fR \fIname\fR
The variant overrides checking on the sensibility of the
.I write
command, as \fBw!\fR does.
.TP
\fBxit\fP \fIname\fR
If any changes have been made
and not written to any file,
writes the buffer out.
Then, in any case, quits.
.TP
( \fB.\fR , \fB.\fR )\|\fByank\fR \fIbuffer\fR \fIcount\fR	abbr: \fBya\fR
Places the specified lines in the named
.I buffer,
for later retrieval via
.I put.
If no buffer name is specified, the lines go to a more volatile place;
see the \fIput\fR command description.
.TP
( \fB.+1\fR ) \fBz\fR \fIcount\fR
Print the next \fIcount\fR lines, default \fIwindow\fR.
.TP
( \fB.\fR ) \fBz\fR \fItype\fR \fIcount\fR
Prints a window of text with the specified line at the top.
If \fItype\fR is `\-' the line is placed at the bottom; a `\fB.\fR' causes
the line to be placed in the center.
A count gives the number of lines to be displayed rather than
double the number specified by the \fIscroll\fR option.
On a \s-1CRT\s0 the screen is cleared before display begins unless a
count which is less than the screen size is given.
The current line is left at the last line printed.
Forms `z=' and `z^' also exist; `z=' places the current line in the
center, surrounds it with lines of `\-' characters and leaves the current
line at this line.  The form `z^' prints the window before `z\-'
would.  The characters `+', `^' and `\-' may be repeated for cumulative
effect.
.TP
\fB!\fR \fIcommand\fR\fR
The remainder of the line after the `!' character is sent to a shell
to be executed.
Within the text of
.I command
the characters 
`%' and `#' are expanded as in filenames and the character
`!' is replaced with the text of the previous command.
Thus, in particular,
`!!' repeats the last such shell escape.
If any such expansion is performed, the expanded line will be echoed.
The current line is unchanged by this command.
.IP
If there has been \*(lq[No\ write]\*(rq of the buffer contents since the last
change to the editing buffer, then a diagnostic will be printed
before the command is executed as a warning.
A single `!' is printed when the command completes.
.TP
( \fIaddr\fR , \fIaddr\fR ) \fB!\fR \fIcommand\fR\fR
Takes the specified address range and supplies it as
standard input to
.I command;
the resulting output then replaces the input lines.
.TP
( $ ) \fB=\fR
Prints the line number of the
addressed line.
The current line is unchanged.
.LP
( \fB.\fR , \fB.\fR ) \fB>\fR \fIcount\fR \fIflags\fR
.br
( \fB.\fR , \fB.\fR ) \fB<\fR \fIcount\fR \fIflags\fR
.RS
Perform intelligent shifting on the specified lines;
\fB<\fR shifts left and \fB>\fR shift right.
The quantity of shift is determined by the
.I shiftwidth
option and the repetition of the specification character.
Only white space (blanks and tabs) is shifted;
no non-white characters are discarded in a left-shift.
The current line becomes the last line which changed due to the
shifting.
.RE
.TP
\fB^D\fR
An end-of-file from a terminal input scrolls through the file.
The
.I scroll
option specifies the size of the scroll, normally a half screen of text.
.LP
( \fB.\fR+1 , \fB.\fR+1 )
.br
( \fB.\fR+1 , \fB.\fR+1 ) |
.RS
An address alone causes the addressed lines to be printed.
A blank line prints the next line in the file.
.RE
.TP
( \fB.\fR , \fB.\fR ) \fB&\fR \fIoptions\fR \fIcount\fR \fIflags\fR
Repeats the previous
.I substitute
command.
.TP
( \fB.\fR , \fB.\fR ) \fB\s+2~\s0\fR \fIoptions\fR \fIcount\fR \fIflags\fR
Replaces the previous regular expression with the previous
replacement pattern from a substitution.
.SS "Regular expressions"
.PP
A regular expression specifies a set of strings of characters.
A member of this set of strings is said to be
.I matched
by the regular expression.
.I Ex
remembers two previous regular expressions:
the previous regular expression used in a
.I substitute
command
and the previous regular expression used elsewhere
(referred to as the previous \fIscanning\fR regular expression.)
The previous regular expression
can always be referred to by a null \fIre\fR, e.g. `//' or `??'.
.PP
The following basic constructs are used to construct
.I magic
mode regular expressions.
.IP \fIchar\fR 15
An ordinary character matches itself.
The characters `\fB^\fR' at the beginning of a line,
`\fB$\fR' at the end of line, 
`\fB*\fR' as any character other than the first,
`\fB.\fR', `\fB\e\fR', `\fB[\fR',
and `\s+2\fB~\fR\s0' are not ordinary characters and
must be escaped (preceded) by `\fB\e\fR' to be treated as such.
.IP \fB^\fR
At the beginning of a pattern
forces the match to succeed only at the beginning of a line.
.IP \fB$\fR
At the end of a regular expression forces the match to
succeed only at the end of the line.
.IP \&\fB.\fR
Matches any single character except
the new-line character.
.IP \fB\e<\fR 
Forces the match
to occur only at the beginning of a \*(lqvariable\*(rq or \*(lqword\*(rq;
that is, either at the beginning of a line, or just before
a letter, digit, or underline and after a character not one of
these.
.IP \fB\e>\fR
Similar to `\e<', but matching the end of a \*(lqvariable\*(rq
or \*(lqword\*(rq, i.e. either the end of the line or before character
which is neither a letter, nor a digit, nor the underline character.
.IP \fB[\fIstring\fR\fB]\fR
Matches any (single) character in the class defined by
.I string.
Most characters in
.I string
define themselves.
.br
\ \ A pair of characters separated by `\fB\-\fR' in
.I string
defines the set of characters collating between the specified lower and upper
bounds, thus `[a\-z]' as a regular expression matches
any (single)
.SM ASCII
lower-case letter.
.br
\ \ If the sequence `\fB[:\fIclass\fB:]\fR' appears in
.IR string ,
where class is one of
.RB ` alnum ',
.RB ` alpha ',
.RB ` blank ',
.RB ` cntrl ',
.RB ` digit ',
.RB ` graph ',
.RB ` lower ',
.RB ` print ',
.RB ` punct ',
.RB ` space ',
.RB ` upper ',
.RB ` xdigit ',
or a locale-specific character class,
all characters that belong to the given class are matched.
Thus `[[:lower:]]' matches any lower-case letter,
possibly including characters beyond the scope of
.SM ASCII.
.br
\ \ If the first character of
.I string
is an `\fB^\fR' then the construct
matches those characters which it otherwise would not;
thus `[^a\-z]' matches anything but an
.SM ASCII
lower-case letter
(and of course a newline).
.br
\ \ Backslash `\e' is interpreted as an escape character.
To place a `\e' character in
.IR string ,
write it twice: `\e\e';
to place any of the characters
`^', `[', or `\-' in
.IR string ,
you escape them with a preceding `\e'.
.br
\ \ Characters also lose their special meaning by position:
`^' is an ordinary character unless immediately
following the initial `[',
`]' is an ordinary character if immediately
following the initial `[' (or `^', if present),
and `\-' is an ordinary character if placed immediately
behind `[' or `^', or before ']'.
.PP
The concatenation of two regular expressions matches the leftmost and
then longest string
which can be divided with the first piece matching the first regular
expression and the second piece matching the second.
.PP
A regular expression may be enclosed between the sequences
`\fB\e(\fR' and `\fB\e)\fR',
which matches whatever the enclosed expression matches.
.PP
Any of the (single character matching) regular expressions mentioned above
or a regular expression surrounded by `\e(' and '\e)'
may be followed by the character `\fB*\fR' to form a regular expression 
which matches any number of adjacent occurrences (including 0) of characters
matched by the regular expression it follows.
.PP
A single character regular expression
or a regular expression surrounded by `\e(' and '\e)'
followed by `\fB\e{\fIm\fB,\fIn\fB\e}\fR'
matches a sequence of \fIm\fP through \fIn\fP occurences, inclusive,
of the single character expression.
The values of \fIm\fP and \fIn\fP
must be non-negative and smaller than 255.
The form `\fB\e{\fIm\fB\e}\fR' matches exactly \fIm\fP occurences,
`\fB\e{\fIm\fB,\e}\fR' matches at least \fIm\fP occurences.
.PP
The character `\s+2\fB~\fR\s0' may be used in a regular expression,
and matches the text which defined the replacement part
of the last
.I substitute
command.
.PP
The sequence `\fB\e\fIn\fR' matches the text that was matched by the
\fIn\fR-th regular subexpression enclosed between `\e(' and `\e)'
earlier in the expression.
.SS "Substitute replacement patterns"
.PP
The basic metacharacters for the replacement pattern are
`\fB&\fR', `\fB~\fR', and `\fB#\fR'; the first two of them are
given as `\fB\e&\fR' and `\fB\e~\fR' when
.I nomagic
is set.
Each instance of `\fB&\fR' is replaced by the characters
which the regular expression matched.
The metacharacter `\fB~\fR' stands, in the replacement pattern,
for the defining text of the previous replacement pattern.
If the entire replacement pattern is `\fB#\fR',
the defining text of the previous replacement pattern is used.
.PP
Other metasequences possible in the replacement pattern
are always introduced by the escaping character `\fB\e\fR'.
The sequence `\fB\e\fIn\fR' is replaced by the text matched
by the \fIn\fR-th regular subexpression enclosed between
`\e(' and `\e)'.
When nested, parenthesized subexpressions are present,
\fIn\fR is determined by counting occurrences of `\e(' starting from the left.
The sequences `\fB\eu\fR' and `\fB\el\fR'
cause the immediately following character in
the replacement to be converted to upper- or lower-case respectively
if this character is a letter.
The sequences `\fB\eU\fR' and `\fB\eL\fR'
turn such conversion on,
either until `\fB\eE\fR' or `\fB\ee\fR' is encountered,
or until the end of the replacement pattern.
.SS "Option descriptions"
.PP
.TP
\fBautoindent\fR, \fBai\fR	default: noai
Can be used to ease the preparation of structured program text.
At the beginning of each
.I append ,
.I change
or
.I insert
command
or when a new line is
.I opened
or created by an
.I append ,
.I change ,
.I insert ,
or
.I substitute
operation within
.I open
or
.I visual
mode,
.I ex
looks at the line being appended after,
the first line changed
or the line inserted before and calculates the amount of white space
at the start of the line.
It then aligns the cursor at the level of indentation so determined.
.IP
If the user then types lines of text in,
they will continue to be justified at the displayed indenting level.
If more white space is typed at the beginning of a line,
the following line will start aligned with the first non-white character
of the previous line.
To back the cursor up to the preceding tab stop one can hit
\fB^D\fR.
The tab stops going backwards are defined at multiples of the
.I shiftwidth
option.
The user
.I cannot
backspace over the indent,
except by sending an end-of-file with a \fB^D\fR.
.IP
Specially processed in this mode is a line with no characters added
to it, which turns into a completely blank line (the white
space provided for the
.I autoindent
is discarded.)
Also specially processed in this mode are lines beginning with
an `^' and immediately followed by a \fB^D\fR.
This causes the input to be repositioned at the beginning of the line,
but retaining the previous indent for the next line.
Similarly, a `0' followed by a \fB^D\fR
repositions at the beginning but without
retaining the previous indent.
.IP
.I Autoindent
doesn't happen in
.I global
commands or when the input is not a terminal.
.TP
\fBautoprint\fR, \fBap\fR	default: ap
Causes the current line to be printed after each
.I delete ,
.I copy ,
.I join ,
.I move ,
.I substitute ,
.I t ,
.I undo
or
shift command.
This has the same effect as supplying a trailing `p'
to each such command.
.I Autoprint
is suppressed in globals,
and only applies to the last of many commands on a line.
.TP
\fBautowrite\fR, \fBaw\fR	default: noaw
Causes the contents of the buffer to be written to the current file
if the user has modified it and gives a
.I next,
.I rewind,
.I stop,
.I tag,
or
.I !
command, or a \fB^^\fR (switch files) or \fB^]\fR (tag goto) command
in
.I visual.
Note, that the
.I edit
and
.I ex
commands do
.B not
autowrite.
In each case, there is an equivalent way of switching when autowrite
is set to avoid the
.I autowrite
(\fIedit\fR
for
.I next ,
.I rewind!
for .I rewind ,
.I stop!
for
.I stop ,
.I tag!
for
.I tag ,
.I shell
for
.I ! ,
and
\fB:e\ #\fR and a \fB:ta!\fR command from within
.I visual).
.TP
\fBbeautify\fR, \fBbf\fR	default: nobeautify
Causes all control characters except tab, newline and form-feed
to be discarded from the input.
A complaint is registered the first time a
backspace character is discarded.
.I Beautify
does not apply to command input.
.TP
\fBdirectory\fR, \fBdir\fR	default: dir=/tmp
Specifies the directory in which
.I ex
places its buffer file.
If this directory in not
writable, then the editor will exit abruptly when it fails to be
able to create its buffer there.
.TP
\fBedcompatible\fR	default: noedcompatible
Causes the presence of absence of
.B g
and
.B c
suffixes on substitute commands to be remembered, and to be toggled
by repeating the suffices.  The suffix
.B r
makes the substitution be as in the
.I ~
command, instead of like
.I &.
.TP
\fBerrorbells\fR, \fBeb\fR	default: noeb
Error messages are preceded by a bell.
Bell ringing in
.I open
and
.I visual
on errors is not suppressed by setting
.I noeb.
If possible the editor always places the error message in a standout mode of the
terminal (such as inverse video) instead of ringing the bell.
.TP
\fBexrc\fR			default: noexrc
If set, the current directory is searched for a
.I .exrc
file on startup.
If this file is found,
its content is treated as
.I ex
commands and executed immediately after the contents of
.I $HOME/.exrc
on startup.
.TP
\fBflash\fR, \fBfl\fR	default: flash
If the terminal provides the \*(lqvisual bell\*(rq capability,
ex will use it instead of the audible bell if
.I flash
is set.
.TP
\fBhardtabs\fR, \fBht\fR	default: ht=8
Gives the boundaries on which terminal hardware tabs are set (or
on which the system expands tabs).
.TP
\fBignorecase\fR, \fBic\fR	default: noic
All upper case characters in the text are mapped to lower case in regular
expression matching.
In addition, all upper case characters in regular expressions are mapped
to lower case except in character class specifications.
.TP
\fBlisp\fR	default: nolisp
\fIAutoindent\fR indents appropriately for
.I lisp
code, and the \fB( ) { } [[\fR and \fB]]\fR commands in
.I open
and
.I visual
are modified to have meaning for \fIlisp\fR.
.TP
\fBlist\fR	default: nolist
All printed lines will be displayed (more) unambiguously,
showing tabs and end-of-lines as in the
.I list
command.
.TP
\fBmagic\fR	default: magic for \fIex\fR and \fIvi\fR, \fINomagic\fR for \fIedit\fR.
If
.I nomagic
is set, the number of regular expression metacharacters is greatly reduced,
with only `^' and `$' having special effects.
In addition the metacharacters
`~'
and
`&'
of the replacement pattern are treated as normal characters.
All the normal metacharacters may be made
.I magic
when
.I nomagic
is set by preceding them with a `\e'.
.TP
\fBmesg\fR	default: mesg
Causes write permission to be turned off to the terminal
while the user is in visual mode, if
.I nomesg
is set.
.TP
\fBmodelines, ml\fR	default: nomodelines
If
.I modelines
is set, then the first 5 lines and the last five lines of the file
will be checked for ex command lines and the comands issued.
To be recognized as a command line, the line must have the string
.B ex:
or
.B vi:
in it.
.\" preceeded by a tab or a space.
This string may be anywhere in the line and anything after the 
.I :
is interpeted as editor commands.  This option defaults to off because
of unexpected behavior when editting files such as
.I /etc/passwd.
.TP
\fBnumber, nu\fR	default: nonumber
Causes all output lines to be printed with their
line numbers.
In addition each input line will be prompted for by supplying the line number
it will have.
.TP
\fBopen\fR	default: open
If \fInoopen\fR, the commands
.I open
and
.I visual
are not permitted.
.\"This is set for
.\".I edit
.\"to prevent confusion resulting from accidental entry to 
.\"open or visual mode.
.TP
\fBoptimize, opt\fR	default: optimize
Throughput of text is expedited by setting the terminal
to not do automatic carriage returns
when printing more than one (logical) line of output,
greatly speeding output on terminals without addressable
cursors when text with leading white space is printed.
.TP
\fBparagraphs,\ para\fR	default: para=IPLPPPQPP\0LIbp
Specifies the paragraphs for the \fB{\fR and \fB}\fR operations in
.I open
and 
.I visual.
The pairs of characters in the option's value are the names
of the macros which start paragraphs.
.TP
\fBprompt\fR	default: prompt
Command mode input is prompted for with a `:'.
.TP
\fBredraw\fR	default: noredraw
The editor simulates (using great amounts of output), an intelligent
terminal on a dumb terminal (e.g. during insertions in
.I visual
the characters to the right of the cursor position are refreshed
as each input character is typed.)
Useful only at very high speed.
.TP
\fBremap\fP	default: remap
If on, macros are repeatedly tried until they are unchanged.
For example, if
.B o
is mapped to
.B O ,
and
.B O
is mapped to
.B I ,
then if
.I remap
is set,
.B o
will map to
.B I ,
but if
.I noremap
is set, it will map to
.B O .
.TP
\fBreport\fR	default: report=5, 2 for \fIedit\fR.
Specifies a threshold for feedback from commands.
Any command which modifies more than the specified number of lines
will provide feedback as to the scope of its changes.
For commands such as
.I global ,
.I open ,
.I undo ,
and
.I visual
which have potentially more far reaching scope,
the net change in the number of lines in the buffer is
presented at the end of the command, subject to this same threshold.
Thus notification is suppressed during a
.I global
command on the individual commands performed.
.TP
\fBscroll\fR	default: scroll=\(12 window
Determines the number of logical lines scrolled when an end-of-file
is received from a terminal input in command mode,
and the number of lines printed by a command mode
.I z
command (double the value of
.I scroll ).
.TP
\fBsections\fR	default: sections=SHNHH\0HU
Specifies the section macros for the \fB[[\fR and \fB]]\fR operations
in
.I open
and
.I visual.
The pairs of characters in the options's value are the names
of the macros which start paragraphs.
.TP
\fBshell\fR, \fBsh\fR	default: sh=/bin/sh
Gives the path name of the shell forked for 
the shell escape command `!', and by the
.I shell
command.
The default is taken from SHELL in the environment, if present.
.TP
\fBshiftwidth\fR, \fBsw\fR	default: sw=8
Gives the width a software tab stop,
used in reverse tabbing with \fB^D\fR when using
.I autoindent
to append text,
and by the shift commands.
.TP
\fBshowmatch, sm\fR	default: nosm
In
.I open
and
.I visual
mode, when a \fB)\fR or \fB}\fR is typed, move the cursor to the matching
\fB(\fR or \fB{\fR for one second if this matching character is on the
screen.  Extremely useful with
.I lisp.
.TP
\fBshowmode, smd\fR	default: nosmd
In
.I visual
mode, show a description of the current editing mode
in the window's lower right corner.
.TP
\fBslowopen, slow\fR	terminal dependent
Affects the display algorithm used in
.I visual
mode, holding off display updating during input of new text to improve
throughput when the terminal in use is both slow and unintelligent.
See
.I "An Introduction to Display Editing with Vi"
for more details.
.TP
\fBtabstop,\ ts\fR	default: ts=8
The editor expands tabs in the input file to be on
.I tabstop
boundaries for the purposes of display.
.TP
\fBtaglength,\ tl\fR	default: tl=0
Tags are not significant beyond this many characters.
A value of zero (the default) means that all characters are significant.
.TP
\fBtags\fR	default: tags=tags /usr/lib/tags
A path of files to be used as tag files for the
.I tag
command.
A requested tag is searched for in the specified files, sequentially.
By default, files called
.B tags
are searched for in the current directory and in /usr/lib
(a master file for the entire system).
.TP
\fBterm\fR	from environment TERM
The terminal type of the output device.
.TP
\fBterse\fR	default: noterse
Shorter error diagnostics are produced for the experienced user.
.TP
\fBwarn\fR	default: warn
Warn if there has been `[No write since last change]' before a `!'
command escape.
.TP
\fBwindow\fR	default: window=speed dependent
The number of lines in a text window in the
.I visual
command.
The default is 8 at slow speeds (600 baud or less),
16 at medium speed (1200 baud),
and the full screen (minus one line) at higher speeds.
.TP
\fBw300,\ w1200,\ w9600\fR
These are not true options but set
.B window
only if the speed is slow (300), medium (1200), or high (9600),
respectively.
They are suitable for an EXINIT
and make it easy to change the 8/16/full screen rule.
.TP
\fBwrapscan\fR, \fBws\fR	default: ws
Searches using the regular expressions in addressing
will wrap around past the end of the file.
.TP
\fBwrapmargin\fR, \fBwm\fR	default: wm=0
Defines a margin for automatic wrapover of text during input in
.I open
and
.I visual
modes.  See
.I "An Introduction to Text Editing with Vi"
for details.
.TP
\fBwriteany\fR, \fBwa\fR	default: nowa
.IP
Inhibit the checks normally made before
.I write
commands, allowing a write to any file which the system protection
mechanism will allow.
.SH "ENVIRONMENT VARIABLES"
.PP
The following environment variables affect the behaviour of ex:
.TP
.B COLUMNS
Overrides the system-supplied number of terminal columns.
.TP
.B EXINIT
Contains commands to execute at editor startup.
If this variable is present, the
.I .exrc
file in the user's home directory is ignored.
.TP
.B HOME
Used to locate the editor startup file.
.TP
.BR LANG ", " LC_ALL
See
.IR locale (7).
.TP
.B LC_CTYPE
Determines the mapping of bytes to characters,
types of characters,
case conversion
and composition of character classes in regular expressions.
.TP
.B LC_MESSAGES
Sets the language used for diagnostic and informal messages.
.TP
.B LINES
Overrides the system-supplied number of terminal lines.
.TP
.B NLSPATH
See
.IR catopen (3).
.TP
.B SHELL
The program file used to execute external commands.
.TP
.B TERM
Determines the terminal type.
.SH FILES
.TP
.B /usr/libexec/expreserve
preserve command
.TP
.B /usr/libexec/exrecover
recover command
.TP
.B /etc/termcap
describes capabilities of terminals
.TP
.B $HOME/.exrc
editor startup file
.TP
.B /var/tmp/Ex\fInnnnnnnnnn\fP
editor temporary
.TP
.B /var/tmp/Rx\fInnnnnnnnnn\fP
named buffer temporary
.TP
.B /var/preserve
preservation directory
.SH DOCUMENTATION
The document
.I "Edit: A tutorial"
(USD:14) provides a comprehensive introduction to
.I edit
assuming no previous knowledge of computers or the 
.SM UNIX
system.
.PP
The
.I "Ex Reference Manual \(en Version 3.7"
(USD:16)
is a comprehensive and complete manual for the command mode features
of
.I ex.
.\"but one cannot learn to use the editor by reading it.
The
.SM \fIUSAGE\fP
section of this page is taken from the manual.
For an introduction to
more advanced forms of editing using the command mode of
.I ex
see the editing documents written by Brian Kernighan for the editor
.I ed;
the material in the introductory and advanced documents works also with
.I ex.
.PP
.I "An Introduction to Display Editing with Vi"
(USD:15)
introduces the display editor
.I vi
and provides reference material on
.I vi.
(This reference now forms the
.IR vi (1)
manual page).
In addition, the
.I "Vi Quick Reference"
card summarizes the commands
of
.I vi
in a useful, functional way, and is useful with the
.I Introduction.
.SH SEE ALSO
awk(1),
ed(1),
grep(1),
sed(1),
grep(1),
vi(1),
catopen(3),
termcap(5),
environ(7),
locale(7),
regex(7)
.SH AUTHOR
Originally written by William Joy.
.PP
Mark Horton has maintained the editor since version 2.7, adding macros,
support for many unusual terminals,
and other features such as word abbreviation mode.
.PP
This version incorporates changes by Gunnar Ritter.
.SH NOTES
.I Undo
never clears the buffer modified condition.
.PP
The
.I z
command prints a number of logical rather than physical lines.
More than a screen full of output may result if long lines are present.
.PP
File input/output errors don't print a name if the command line \fB`\-'\fR
option is used.
.\".PP
.\"There is no easy way to do a single scan ignoring case.
.PP
The editor does not warn if text is placed in named buffers and not used
before exiting the editor.
.PP
Null (00) characters are converted to 0200 characters
when reading input files,
and cannot appear in resultant files.
.PP
LC_COLLATE locales are ignored;
collating symbols `[.c.]'
and equivalence classes `[=c=]'
in bracket expressions are recognized but useless
since `c' is restricted to a single character
and is the only character matched;
range expressions `[a\-m]' are always evaluated in byte order.