ed.1

<B>Digital的Unix操作系统VAX 4.2源码</B>

given
.I "command list\^"
is executed with \fB.\fP initially set to that line.
A single command or the first of a list of commands
appears on the same line as the global command.
All lines of a multi-line list except the last line must be ended with a \fB\^\e\fP;
.B a,
.B i,
and
.B c
commands and associated input are permitted;
the \fB.\fP terminating input mode may be omitted if it would be the
last line of the
.IR "command list" .
An empty
.I "command list\^"
is equivalent to the
.B p
command.
The
.B g,
.B G,
.B v,
and
.B V
commands
are
.I not\^
permitted in the
.IR "command list" .
See also
RESTRICTIONS
and the last paragraph before
FILES
below.
.HP
.BI (\|1\|,\|$\|)G/ \s-1RE\s+1 /\^
.br
In the interactive Global
command, the first step
is to mark every line that matches the given
\s-1RE\s+1.
Then, for every such line, that line is printed, \fB.\fP is changed to that line, and
any
.I one\^
command (other than one of the
.B a,
.B c,
.B i,
.B g,
.B G,
.B v,
and
.B V
commands)
may be input and is executed.
After the execution of that command, the next marked line is printed, and so on;
a new-line acts as a null command;
an \fB&\fP causes the re-execution of the most recent command executed within
the current invocation of
.IR G .
Note that the
commands input
as part of the execution of the
.B G
command
may
address and affect
.I any\^
lines in the buffer.
The
.B G
command can be terminated by an interrupt signal (\s-1ASCII\s0 \s-1DEL\s0 or \s-1BREAK\s0).
.HP
.br
.B h
.br
The 
.B help
command gives a short error message that explains
the reason for the most recent \fB?\fP diagnostic.
.HP
.B H
.br
The 
.B help
command causes
.PN ed
to enter a mode in which error messages are
printed for all subsequent \fB?\fP diagnostics.
It will also explain the previous \fB?\fP if
there was one.
The
.B H
command alternately turns this mode
on and off; it is initially off.
.HP
.B (\|.\|)i
.br
.ns
.HP
<text>
.br
.ns
.HP
.if t .rs
.if t .sp -.5v
\&\fB.\fP
.br
The insert
command inserts the given text before the addressed line;
\&\fB.\fP is left at the last inserted line, or, if there were none,
at the addressed line.
This command differs from the
.B a
command only in the placement of the
input
text.
Address 0 is not legal for this command.
The maximum number of characters that may be entered from a
terminal is 256 per line (including the new line character).
.HP
.B (\|.\|,\|.+1\|)j
.br
The join
command joins contiguous lines by removing the appropriate new-line characters.
If exactly one address is given, this command does nothing.
.HP
.BI (\|.\|)k x\^
.br
The mark command marks the addressed line with
name
.IR x ,
which must be a lower-case letter.
The address \fI\(fmx\fP\^ then addresses this line;
\&\fB.\fP is unchanged.
.HP
.B (\|.\|,\|.\|)l
.br
The list
command
prints the addressed lines in an unambiguous way:
a few non-printing characters (for example,
.IR "tab, backspace" )
are represented by (hopefully) mnemonic overstrikes, all other non-printing
characters are
printed in octal,
and long lines are folded.
An
.B l
command may be appended to any other command
other than
.B e,
.B f,
.B r,
or
.B w.
.HP
.BI (\|.\|,\|.\|)m a\^
.br
The 
.B move
command repositions the addressed line(s) after the line
addressed by
.I a.
Address 0 is legal for
.I a\^
and causes the addressed line(s) to be moved to
the beginning of the file;
it is an error if address
.I a\^
falls within the range of moved lines;
\&\fB.\fP is left at the last line moved.
.HP
.B (\|.\|,\|.\|)n
.br
The number
command prints the addressed lines,
preceding each line by its
line number and a tab character;
\&\fB.\fP is left at the last line printed.
The
.B n
command
may
be appended to any other command
other than
.B e,
.B f,
.B r,
or
.B w.
.HP
.B (\|.\|,\|.\|)p
.br
The print
command prints the addressed lines;
\&\fB.\fP is left at the last line printed.
The
.B p
command
may
be appended to any other command
other than
.B e,
.B f,
.B r,
or
.B w;
for example, \fIdp\fP\^
deletes the current line and prints the
new current line.
.HP
.br
.B P
.br
The editor will prompt with a \fB\(**\fP for
all subsequent commands.
The
.B P
command alternately turns this mode on and off; it is
initially off.
.HP
.B q
.br
The quit
command causes
.PN ed
to exit.
No automatic write
of a file is done
(but see DIAGNOSTICS below).
.HP
.br
.B Q
.br
The editor exits without
checking if changes have been made in the buffer since the
last
.B w
command.
.HP
.BI (\|$\|)r " file\^"
.br
The read
command
reads in the given file after the addressed line.
If no file name is given,
the currently-remembered file name, if any, is used
(see
.B e
and
.B f
commands).
The currently-remembered file name is
.I not\^
changed unless
.I file\^
is the very first file name
mentioned
since
.PN ed
was invoked.
Address 0 is legal for
.I r\^
and causes the
file to be read at the beginning of the buffer.
If the read is successful, the number of characters
read is typed;
\&\fB.\fP is set to the last line read in.
If
.I file\^
is replaced by \fB!\fP, the rest of the line
is taken to be a
shell (\fIsh\fP\^(1))
command whose output is to be read.
For example, "$r !ls" appends current directory
to the end of the file being edited.
Such a
shell
command is
.B not
remembered as the current file name.
.HP
.BI (\|.\|,\|.\|)s/ \s-1RE\s+1 / replacement /\^
\ \ \ \ \ \ \ \ or
.br
.ns
.HP
.BI (\|.\|,\|.\|)s/ \s-1RE\s+1 / replacement /g\^
.br
The substitute
command searches each addressed
line for an occurrence of the specified \s-1RE\s+1.
In each line in which a match is found,
all (non-overlapped) matched strings are
replaced by the
.I replacement\^
if the global replacement indicator \fBg\fP appears after the command.
If the global indicator does not appear, only the first occurrence
of the matched string is replaced.
It is an error for the substitution to fail on
.I all\^
addressed lines.
Any character other than space or new-line
may be used instead of \fB/\fP to delimit the \s-1RE\s+1
and
the
.IR replacement;
\&\fB.\fP is left at the last line on which a substitution occurred.
See also the last paragraph before
FILES
below.
.IP
An ampersand (\^\fB&\fP\^) appearing in the
.I replacement\^
is replaced by the string matching the \s-1RE\s+1 on the current line.
The special meaning of \fB&\fP in this context may be
suppressed by preceding it by \fB\^\e\fP.
As a more general feature,
the characters
\fB\^\e\fP\fIn\fP\^,
where
.I n\^
is a digit,
are replaced by the text matched by the
.IR n \-th
regular subexpression
of the specified \s-1RE\s+1
enclosed between \fB\^\e(\fP and \fB\^\e)\fP.
When
nested parenthesized subexpressions
are present,
.I n\^
is determined by counting occurrences of \fB\^\e(\fP starting from the left.
When the character \fB%\fP is the only character
in the
.IR replacement,
the
.I replacement\^
used in the most recent substitute
command is used as the
.I replacement\^
in the current substitute command.
The \fB%\fP loses its special meaning when it is
in a replacement string of more than one
character or is preceded by a \fB\^\e\fP.
.IP
A line may be split by substituting a new-line character into it.
The new-line in the
.I replacement\^
must be escaped by preceding it by \fB\^\e\fP.
Such substitution cannot be done as part of a
.B g
or
.B v
command list.
.HP
.BI (\|.\|,\|.\|)t a\^
.br
This command acts just like the
.B m
command, except that a
.I copy\^
of the addressed lines is placed
after address
.I a\^
(which may be 0);
\&\fB.\fP is left at the last line of the copy.
.HP
.B u
.br
The
.B undo
command nullifies the effect of the most recent
command that modified anything in the buffer, namely
the most recent
.B a,
.B c,
.B d,
.B g,
.B i,
.B j,
.B m,
.B r,
.B s,
.B t,
.B v,
.B G,
or
.B V
command.
.HP
.BI (\|1\|,\|$\|)v/ \s-1RE\s+1 / "command list\^"
.br
This command is the same as the global command
.B g
except that the
.I "command list\^"
is executed
with \fB.\fP initially set to every line
that does
.I not\^
match the
\s-1RE\s+1.
.HP
.BI (\|1\|,\|$\|)V/ \s-1RE\s+1 /\^
.br
This command is the same as the interactive global command
.B G
except
that the lines that are marked during the first step are those that do
.I not\^
match the
\s-1RE\s+1.
.HP
.BI (\|1\|,\|$\|)w " file\^"
.br
The write
command writes the addressed lines into
the named file.
If the file does not exist,
it is created with mode 666 (readable and writable by everyone),
unless your
.I umask\^
setting
(see
.IR sh (1))
dictates otherwise.
The currently-remembered file name is
.I not\^
changed unless
.I file\^
is the very first file name mentioned since
.PN ed
was invoked.
If no file name is given,
the currently-remembered file name, if any, is used
(see
.B e
and
.B f
commands);
\&\fB.\fP is unchanged.
If the command is successful, the number of characters written is
typed.
If
.I file\^
is replaced by \fB!\fP, the rest of the line
is taken to be a
shell (\fIsh\fP\^(1))
command whose standard input is the addressed lines.
Such a
shell
command is
.I not\^
remembered as the current file name.
.HP
.B (\|$\|)=
.br
The line number of the addressed line is typed;
\&\fB.\fP is unchanged by this command.
.HP
.BI ! "shell\| command\^"
.br
The remainder of the line after the \fB!\fP is sent
to the UNIX System
shell (\fIsh\fP\^(1)) to be interpreted as a command.
Within the text of that command, the unescaped character
.B %
is replaced with the remembered file name;
if a
.B !
appears as the first character of the shell command,
it is replaced with the text of the previous shell command.
Thus,
.B !!
will repeat the last shell command.
If any expansion is performed, the expanded line is echoed;
\&\fB.\fP is unchanged.
.HP
.BR (\|.+1\|) <new-line>
.br
An address alone on a line causes the addressed line to be printed.
A new-line alone is equivalent to \fB.+1p\fP; it is useful
for stepping forward through the buffer.
.PP
If an interrupt signal (\s-1ASCII\s0 \s-1DEL\s0 or \s-1BREAK\s0) is sent,
.PN ed
prints a \fB?\fP and returns to
.B its
command level.
.NXR "ed line editor" "interrupt signal"
.PP
Some size limitations:
512 characters per line,
256 characters per global command list,
64 characters per file name,
and 128K characters in the buffer.
The limit on the number of lines depends on the amount of user memory:
each line takes 1 word.
.PP
When reading a file,
.PN ed
discards ASCII NUL characters
and all characters after the last new-line.
Files
(for example,
.BR a.out )
that
contain characters not in the
ASCII
set (bit
8 on) cannot be edited by
.PN ed .
.PP
If the closing delimiter of a \s-1RE\s+1 or of a
replacement string (for example, \fB/\fP) would be the last
character before a new-line,
that delimiter may be omitted, in
which case the addressed line
is printed.
The following pairs of commands are equivalent:
.PD 0
.RS
.TP 10
s/s1/s2
s/s1/s2/p
.TP
g/s1
g/s1/p
.TP
?s1
?s1?
.RE
.SH Restrictions
.NXR "ed line editor" "restricted"
A
.B !
command cannot be subject to a
.B g
or a
.B v
command.
.PP
The
.B !
command
and the
.B !
escape from the
.B e,
.B r,
and
.B w
commands
cannot be used if the the editor is invoked from a restricted
shell.  For further information, see 
.MS sh 1 .
.PP
The sequence \fB\^\en\fP in a \s-1RE\s+1 does not
match a new-line character.
.PP
The
.B l
command mishandles DEL.
.SH Diagnostics
.NXR "ed line editor" "diagnostics"
.TP 10
.B ?
for command errors.
.TP
.BI ? file\^
for an inaccessible file.
.br
(use the help
and Help
commands for detailed explanations).
.PD
.PP
If changes have been made in the buffer since the last
.B w
command that wrote the entire buffer,
.PN ed
warns the user if an attempt is made to destroy
.PN ed 's
buffer via the
.B e
or
.B q
commands:
it
prints
.B ?
and
allows one to continue editing.
A second
.B e
or
.B q
command
at this point will take effect.
The \fB\-\fP command-line option inhibits this feature.
.SH Files
.PD 0
.TP 10
/tmp/e#
temporary;
# is the process number.
.TP
ed\s+4.\s-4hup
work is saved here if the terminal is hung up.
.SH See Also
grep(1), sed(1), sh(1), stty(1)