Almost all text input on the UNIXoperating system is done with the text-editor ed. This memorandum is a tutorial guide to help beginners get started with text editing.
Although it does not cover everything, it does discuss enough for most users' day-to-day needs. This includes printing, appending, changing, deleting, moving and inserting entire lines of text; reading and writing files; context searching and line addressing; the substitute command; the global commands; and the use of special characters for advanced editing.
Ed is a ``text editor'', that is, an interactive program for creating and modifying ``text'', using directions provided by a user at a terminal. The text is often a document like this one, or a program or perhaps data for a program.
This introduction is meant to simplify learning ed. The recommended way to learn ed is to read this document, simultaneously using ed to follow the examples, then to read the description in section I of the UNIX Programmer's Manual, all the while experimenting with ed. (Solicitation of advice from experienced users is also useful.)
Do the exercises! They cover material not completely discussed in the actual text. An appendix summarizes the commands.
This is an introduction and a tutorial. For this reason, no attempt is made to cover more than a part of the facilities that ed offers (although this fraction includes the most useful and frequently used parts). When you have mastered the Tutorial, try Advanced Editing on UNIX. Also, there is not enough space to explain basic UNIX procedures. We will assume that you know how to log on to UNIX, and that you have at least a vague understanding of what a file is. For more on that, read UNIX for Beginners.
You must also know what character to type as the end-of-line on your particular terminal. This character is the RETURN key on most terminals. Throughout, we will refer to this character, whatever it is, as RETURN.
We'll assume that you have logged in to
your system
and it has just printed the prompt character,
usually either a
$
or a
%.
The
easiest way to get
ed
is to type
ed (followed by a return)
You are now ready to go -
ed
is waiting for you to tell it what to do.
As your first problem, suppose you want to create some text starting from scratch. Perhaps you are typing the very first draft of a paper; clearly it will have to start somewhere, and undergo modifications later. This section will show how to get some text in, just to get started. Later we'll talk about how to change it.
When ed is first started, it is rather like working with a blank piece of paper - there is no text or information present. This must be supplied by the person using ed; it is usually done by typing in the text, or by reading it into ed from a file. We will start by typing in some text, and return shortly to how to read files.
First a bit of terminology. In ed jargon, the text being worked on is said to be ``kept in a buffer.'' Think of the buffer as a work space, if you like, or simply as the information that you are going to be editing. In effect the buffer is like the piece of paper, on which we will write things, then change some of them, and finally file the whole thing away for another day.
The user tells ed what to do to his text by typing instructions called ``commands.'' Most commands consist of a single letter, which must be typed in lower case. Each command is typed on a separate line. (Sometimes the command is preceded by information about what line or lines of text are to be affected - we will discuss these shortly.) Ed makes no response to most commands - there is no prompting or typing of messages like ``ready''. (This silence is preferred by experienced users, but sometimes a hangup for beginners.)
The first command is
append,
written as the letter
a
all
by itself.
It means ``append (or add) text lines to the buffer,
as I type them in.''
Appending is rather like
writing fresh material on a piece of paper.
So to enter lines of text into the buffer,
just type an
a
followed by a
RETURN,
followed by the lines of text you want, like this:
a
Now is the time
for all good men
to come to the aid of their party.
.
The only way to stop appending is to type a line that contains only a period. The ``.'' is used to tell ed that you have finished appending. (Even experienced users forget that terminating ``.'' sometimes. If ed seems to be ignoring you, type an extra line with just ``.'' on it. You may then find you've added some garbage lines to your text, which you'll have to take out later.)
After the append command has been done, the buffer will
contain the three lines
Now is the time
for all good men
to come to the aid of their party.
The
``a''
and ``.'' aren't there, because they are
not text.
To add more text to what you already have, just issue another a command, and continue typing.
If at any time you make an error in the commands you type to
ed,
it will tell you by typing
?
This is about as cryptic as it can be,
but with practice, you can usually
figure out how you goofed.
It's likely that you'll want to save your text for later use.
To write out the contents of the buffer onto a file,
use the
write
command
w
followed by the filename you want to write on.
This will copy the buffer's contents
onto the specified file
(destroying any previous information on the file).
To save
the text on a file named
junk,
for example, type
w junk
Leave a space between
w
and the file name.
Ed
will respond by printing
the number of characters it wrote out.
In this case,
ed
would respond with
68
(Remember that blanks and the return character at the end of each
line are included in the character count.)
Writing a file just makes a copy of the text - the
buffer's contents are not disturbed, so you can go on adding
lines to it.
This is an important point.
Ed
at all times works on a copy
of a file, not the file itself.
No change in the contents
of a file takes place until you give a
w
command.
(Writing out the text onto a file from time to time as it is being
created is a good idea, since if the system crashes or if you make some horrible mistake, you will lose
all the text in the buffer but any text that was written onto
a file is relatively safe.)
To terminate a session with
ed,
save the text you're working on
by writing it onto a file using the
w
command,
and then type the command
q
which
stands for
quit.
The system will respond with
the prompt character
($
or
%).
At
this point your buffer vanishes, with all its text,
which is why you want to write it out before quitting.**
Enter
ed
and
create some text using
a
. . . text . . .
.
Write it out using
w.
Then leave
ed
with the
q
command, and print the file,
to see that everything worked.
(To print a file, say
pr filename
or
cat filename
in response to
the prompt character.
Try both.)
A common way to get text into the buffer is to read it
from a file in the file system.
This is what you do to edit text
that you saved with the
w
command in a previous session.
The
edit
command
e
fetches the entire contents of a file into the buffer.
So if you had saved the three lines
``Now is the time'', etc.,
with a
w
command in an earlier session,
the
ed
command
e junk
would fetch the entire contents of the file
junk
into the buffer, and respond
68
which is the number of characters in
junk.
If anything was already in the buffer, it is deleted first.
If you use the
e
command to read a file into the buffer,
then you need not use a file name after a subsequent
w
command;
ed
remembers the last file name used in an
e
command,
and
w
will write on this file.
Thus a good way to operate is
ed
e file
[editing session]
w
q
This way, you can simply say
w
from time to time,
and be secure in the knowledge that
if you got the file name right at the beginning,
you are writing into the proper file each time.
You can find out at any time what file name
ed
is remembering by typing the
file
command
f.
In this example,
if you typed
f
ed
would reply
junk
Sometimes you want to read a file into the buffer
without destroying anything that is already there.
This is done by the
read
command
r.
The command
r junk
will read the file
junk
into the buffer;
it adds it
to the end of whatever is already in the buffer.
So if you do a read after
an edit:
e junk
r junk
the buffer will contain
two
copies of the text (six lines).
Now is the time
for all good men
to come to the aid of their party.
Now is the time
for all good men
to come to the aid of their party.
Like the
w
and
e
commands,
r
prints
the
number of characters read in, after the reading operation is complete.
Generally speaking, r is much less used than e.
Experiment with the
e
command -
try reading and printing various files.
You may get an error
?name,
where
name
is the name of a file;
this means that the file doesn't exist,
typically because you spelled the file name wrong,
or perhaps that you are not allowed to read or write it.
Try alternately reading and appending to see that they work
similarly.
Verify that
ed filename
is exactly equivalent to
ed
e filename
What does
f filename
do?
To
print
or list the contents of the buffer (or parts
of it) on the terminal, use the print command
p
The way this is done is as follows.
Specify the lines where
you want printing to begin and where you want it to end,
separated by a comma, and
followed by the letter
p.
Thus to print the first two lines of the buffer, for
example, (that is, lines 1 through 2) say
1,2p (starting line=1, ending line=2 p)
Ed
will respond with
Now is the time
for all good men
Suppose you want to print
all
the lines in the buffer.
You could use
1,3p
as above if you knew there were exactly
3 lines in the buffer.
But in general, you don't
know how many there are, so what do you use for the ending
line number?
Ed
provides a shorthand symbol for ``line number of
last line in buffer'' - the dollar sign
$.
Use it this
way:
1,$p
This will print
all
the lines in the buffer (line 1 to last line.)
If you want to stop the printing before it is finished,
push the
DEL
or Delete key;
ed
will type
?
and wait for the next command.
To print the
last
line of the buffer, you could use
$,$p
but
ed
lets you abbreviate this to
$p
You can print any single line by typing the line
number followed by a
p.
Thus
1p
produces the response
Now is the time
which is the first line of the buffer.
In fact,
ed
lets you abbreviate even further:
you can print any single line by typing
just
the line number - no need to type the letter
p.
So if you say
$
ed
will print the last line of the buffer.
You can also use
$
in combinations like
$-1,$p
which prints the last two lines of the buffer.
This helps when you want to see how far you got in typing.
As before, create some text using the
a
command and
experiment with the
p
command.
You will find, for example,
that you can't print line 0 or a line beyond
the end of the buffer, and that attempts
to print a buffer in reverse order by saying
3,1p
don't work.
Suppose your buffer still contains the six lines as above,
that you have just typed
1,3p
and
ed
has printed the three lines for you.
Try typing just
p (no line numbers)
This will print
to come to the aid of their party.
which is the third line of the buffer.
In fact it is the last
(most recent) line that you have done anything with.
(You just printed it!)
You can
repeat this
p
command without line numbers, and
it will continue to print line 3.
The reason is that
ed
maintains a record of the last line
that you did anything to (in this case, line 3, which you
just printed) so that it can be used instead of an explicit
line number.
This most recent line is referred to by the
shorthand symbol
. (pronounced ``dot'').
Dot is a line number in the same way that
$
is; it means
exactly ``the current line'', or loosely,
``the line you most recently did something to.''
You
can use it in several ways - one possibility
is to say
.,$p
This will print all the lines from (including) the current
line to the
end of the buffer.
In our example these are lines 3 through 6.
Some commands change the value of dot, while others do not. The p command sets dot to the number of the last line printed; the last command will set both . and $ to 6.
Dot is most useful when used in combinations like this one:
.+1 (or equivalently, .+1p)
This means ``print the next line'' and is a handy way to step
slowly through a buffer.
You can also say
.-1 (or .-1p )
which means ``print the line
before
the current line.''
This enables you to go backwards if you wish.
Another useful one is something like
.-3,.-1p
which prints the previous three lines.
Don't forget that all of these change the value of dot.
You can find out what dot is at any time by typing
.=
Ed
will respond by printing the value of dot.
Let's summarize some things about the p command and dot. Essentially p can be preceded by 0, 1, or 2 line numbers. If there is no line number given, it prints the ``current line'', the line that dot refers to. If there is one line number given (with or without the letter p), it prints that line (and dot is set there); and if there are two line numbers, it prints all the lines in that range (and sets dot to the last line printed.) If two line numbers are specified the first can't be bigger than the second (see Exercise 2.)
Typing a single return will cause printing of the next line - it's equivalent to .+1p. Try it. Try typing a -; you will find that it's equivalent to .-1p.
Suppose you want to get rid of the three extra lines in the buffer.
This is done by the
delete
command
d
Except that
d
deletes lines instead of printing them,
its action is similar to that of
p.
The lines to be deleted are specified for
d
exactly as they are for
p:
starting line, ending line d
Thus the command
4,$d
deletes lines 4 through the end.
There are now three lines left, as you can check by using
1,$p
And notice that
$
now is line 3!
Dot
is set to the next line after the last line deleted,
unless the last line deleted is the last line in the buffer.
In that case, dot is set to
$.
Experiment with a, e, r, w, p and d until you are sure that you know what they do, and until you understand how dot, $, and line numbers are used.
If you are adventurous, try using line numbers with
a,
r
and
w
as well.
You will find that
a
will append lines
after
the line number that you specify (rather than after dot); that
r
reads
a file in
after
the line number you specify (not necessarily
at the end of the buffer); and that
w
will write out exactly the lines
you specify, not necessarily the whole buffer.
These variations are sometimes handy.
For instance you can insert a file at the beginning of a buffer
by saying
0r filename
and you can enter lines at the beginning of the buffer
by saying
0a
. . . text . . .
.
Notice that
.w
is
very
different from
.
w
We are now ready to try one of the most important
of all commands - the substitute command
s
This is the command
that is used to change individual
words or letters within a line or group of lines.
It is what you use, for example, for correcting spelling
mistakes and typing errors.
Suppose that by a typing error, line 1 says
Now is th time
- the
e
has been left off
the.
You can use
s
to fix this up as follows:
1s/th/the/
This says: ``in line 1, substitute for the characters
th
the characters
the.''
To verify
that it works
(ed
will not print
the result automatically) say
p
and get
Now is the time
which is what you wanted.
Notice that dot must have been set to the line
where the substitution took place, since the
p
command
printed that line.
Dot is always set this way with the
s
command.
The general way to use the substitute command is
startingline, endingline s/change this/to this/
Whatever string of characters is between the first pair of
slashes is replaced by whatever is between the second pair,
in
all
the lines between
starting-line
and
ending-line.
Only the first occurrence on each line is changed, however.
If you want to change
every
occurrence, see Exercise 5.
The rules for line numbers are the same as those for
p,
except that dot is set to the last line changed.
(But there is a trap for the unwary: if no substitution
took place, dot is
not
changed.
This causes an error
?
as a warning.)
Thus you can say
1,$s/speling/spelling/
and correct the first spelling mistake
on each line
in the text.
(This is useful for people who are consistent
misspellers!)
If no line numbers are given, the
s
command assumes we mean
``make the substitution on line dot'', so it changes things only
on the current line.
This leads to the very common sequence
s/something/something else/p
which makes some correction on the
current line, and then prints it, to make sure it
worked out right.
If it didn't,
you can try again.
(Notice that there is
a
p
on the same line as the
s
command.
With few exceptions,
p
can follow any command;
no other multi-command lines are legal.)
It's also legal to say
s/ . . . //
which means ``change the first
string of characters to
``nothing'',
i.e.,
remove them.
This is useful for deleting extra words in a line or removing extra
letters from words.
For instance, if you had
Nowxx is the time
you can say
s/xx//p
to get
Now is the time
Notice that
//
(two adjacent slashes) means ``no characters'', not a blank.
There
is
a difference!
(See below for another meaning of
//.)
Experiment with the substitute command.
See what happens if you
substitute for some word on a line with several occurrences of that word.
For example, do this:
a
the other side of the coin
.
s/the/on the/p
You will get
on the other side of the coin
A substitute command changes only the first occurrence of the first string.
You can change all occurrences by adding a
g
(for ``global'')
to the
s
command, like this:
s/ . . . / . . . /gp
Try other characters instead of slashes to delimit the two sets
of characters in the
s
command - anything should work
except blanks or tabs.
(If you get funny results using any of the characters
^ . $ [ * \ &
read the section on ``Special Characters''.)
With the substitute command mastered, you can move on to another highly important idea of ed - context searching.
Suppose you have the original three line text in the buffer:
Now is the time
for all good men
to come to the aid of their party.
Suppose you want to find the line that contains
their
so
you can change it to
the.
Now with only three lines in the buffer, it's pretty easy
to keep track of what line the word
their
is on.
But if the buffer contained several hundred lines,
and you'd been making changes, deleting and rearranging lines,
and so on, you would no longer really know what this line
number would be.
Context searching is simply a method of specifying the desired line,
regardless of what its number is,
by specifying some context on it.
The way to say ``search for a line
that contains this particular string of characters''
is to type
/string of characters we want to find/
For example,
the
ed
command
/their/
is a context search which
is sufficient to find the desired line -
it will locate the next occurrence of
the characters between slashes (``their'').
It also sets dot to that line
and prints the line for verification:
to come to the aid of their party.
``Next occurrence'' means that
ed
starts looking for the string at line
.+1,
searches to the end of the buffer,
then continues at line 1 and searches to line dot.
(That is, the search ``wraps around'' from
$
to
1.)
It scans all the lines in the buffer until it either finds the desired line
or gets back to dot again.
If the given string of characters can't be found in any line,
ed
types the error message
?
Otherwise it prints the line it found.
You can do both the search for the desired line
and
a
substitution all at once, like this:
/their/s/their/the/p
which will yield
to come to the aid of the party.
There were three parts to that last command:
context search for the desired line, make the substitution, print the line.
The expression /their/ is a context search expression. In their simplest form, all context search expressions are like this - a string of characters surrounded by slashes. Context searches are interchangeable with line numbers, so they can be used by themselves to find and print a desired line, or as line numbers for some other command, like s. They were used both ways in the examples above.
Suppose the buffer contains the three familiar lines
Now is the time
for all good men
to come to the aid of their party.
Then the
ed
line numbers
/Now/+1
/good/
/party/-1
are all context search expressions, and they all refer
to the same line (line 2).
To make a change in line 2,
you could say
/Now/+1s/good/bad/
or
/good/s/good/bad/
or
/party/-1s/good/bad/
The choice is dictated only by convenience.
You could print all three lines by, for instance
/Now/,/party/p
or
/Now/,/Now/+2p
or by any number of similar combinations.
The first one of these might be better if you don't
know how many lines are involved.
(Of course, if there were only three lines in the buffer,
you'd use
1,$p
but not if there were several hundred.)
The basic rule is: a context search expression is the same as a line number, so it can be used wherever a line number is needed.
Experiment with context searching. Try a body of text with several occurrences of the same string of characters, and scan through it using the same context search.
Try using context searches as line numbers for the substitute, print and delete commands. (They can also be used with r, w, and a.)
Try context searching using ?text? instead of /text/. This scans lines in the buffer in reverse order rather than normal. This is sometimes useful if you go too far while looking for some string of characters - it's an easy way to back up.
(If you get funny results with any of the characters
^ . $ [ * \ &
read the section on ``Special Characters''.)
Ed
provides a shorthand for repeating a context search
for the same string.
For example,
the
ed
line number
/string/
will find the next occurrence of
string.
It often happens that this is not the desired line,
so the search must be repeated.
This can be done by typing merely
//
This shorthand stands for ``the most recently used
context search expression.''
It can
also be used as the first string of the substitute
command, as in
/string1/s//string2/
which will find the next occurrence of
string1
and replace it by
string2.
This can save a lot of typing.
Similarly
??
means ``scan backwards for the same expression.''
This section discusses the
change
command
c
which is used to change
or replace a group of one or more lines,
and the
insert
command
i
which is used for inserting a group of one or more lines.
``Change'', written as
c
is used to replace a number of lines with different lines, which
are typed in at the terminal.
For example,
to change lines
.+1
through
$
to something else, type
.+1,$c
. . . type the lines of text you want here . . .
.
The lines you type between the
c
command and
the
.
will take the place of the original lines between
start line and end line.
This is most useful in replacing a line
or several lines which have errors in them.
If only one line is specified in the c command, then just that line is replaced. (You can type in as many replacement lines as you like.) Notice the use of . to end the input - this works just like the . in the append command and must appear by itself on a new line. If no line number is given, line dot is replaced. The value of dot is set to the last line you typed in.
``Insert'' is similar to append - for instance
/string/i
. . . type the lines to be inserted here . . .
.
will insert the given text
before
the next line that contains ``string''.
The text between
i
and
.
is
inserted before
the specified line.
If no line number is specified dot is used.
Dot is set to the last line inserted.
``Change'' is rather like a combination of
delete followed by insert.
Experiment to verify that
start, end d
i
. . . text . . .
.
is almost the same as
start, end c
. . . text . . .
.
These are not
precisely
the same
if line
$
gets deleted.
Check this out.
What is dot?
Experiment with
a
and
i,
to see that they are
similar, but not the same.
You will observe that
linenumber a
. . . text . . .
.
appends
after
the given line, while
linenumber i
. . . text . . .
.
inserts
before
it.
Observe that if no line number is given,
i
inserts before line dot, while
a
appends
after line dot.
The move command
m
is used for cutting and pasting -
it lets you move a group of lines
from one place to another in the buffer.
Suppose you want to put the first three lines of the buffer at the end instead.
You could do it by saying:
1,3w temp
$r temp
1,3d
(Do you see why?)
but you can do it a lot easier with the
m
command:
1,3m$
The general case is
start line, end line m after this line
Notice that there is a third line to be specified -
the place where the moved stuff gets put.
Of course the lines to be moved can be specified
by context searches;
if you had
First paragraph
. . .
end of first paragraph.
Second paragraph
. . .
end of second paragraph.
you could reverse the two paragraphs like this:
/Second/,/end of second/m/First/-1
Notice the
-1:
the moved text goes
after
the line mentioned.
Dot gets set to the last line moved.
The
global
command
g
is used to execute one or more
ed
commands on all those lines in the buffer
that match some specified string.
For example
g/peling/p
prints all lines that contain
peling.
More usefully,
g/peling/s//pelling/gp
makes the substitution everywhere on the line,
then prints each corrected line.
Compare this to
1,$s/peling/pelling/gp
which only prints the last line substituted.
Another subtle difference is that
the
g
command
does not give a
?
if
peling
is not found
where the
s
command will.
There may be several commands
(including
a,
c,
i,
r,
w,
but not
g);
in that case,
every line except the last must end with a backslash
\:
g/xxx/.-1s/abc/def/\
.+2s/ghi/jkl/\
.-2,.p
makes changes in the lines before and after each line
that contains
xxx,
then prints all three lines.
The
v
command is the same as
g,
except that the commands are executed on every line
that does
not
match the string following
v:
v/ /d
deletes every line that does not contain a blank.
You may have noticed that things just don't work right when you used
some characters like
.,
*,
$,
and others in
context searches and the substitute command.
The reason is rather complex, although the cure is simple.
Basically,
ed
treats these characters as special, with special meanings.
For instance,
in a context search or the first string of the substitute command only,
.
means ``any character,'' not a period, so
/x.y/
means ``a line with an
x,
any character,
and a
y,''
not
just ``a line with an
x,
a period, and a
y.''
A complete list of the special characters
that can cause trouble is the following:
^ . $ [ * \
Warning:
The backslash character
\
is special to
ed.
For safety's sake,
avoid it where possible.
If you have to use one of the special characters
in a substitute command,
you can turn off its magic meaning temporarily
by preceding it with the backslash.
Thus
s/\\\.\*/backslash dot star/
will change
\.*
into ``backslash dot star''.
Here is a hurried synopsis of the other special characters.
First, the circumflex
^
signifies
the beginning of a line.
Thus
/^string/
finds
string
only if it is at the beginning of a line:
it will find
string
but not
the string...
The dollar-sign
$
is just the opposite of the circumflex;
it means the end of a line:
/string$/
will only find an occurrence of
string
that is at the end of some line.
This implies, of course,
that
/^string$/
will find only a line that contains just
string,
and
/^.$/
finds a line containing exactly one character.
The character
.,
as we mentioned above,
matches anything;
/x.y/
matches any of
x+y
x-y
x y
x.y
This is useful in conjunction with
*,
which is a repetition character;
a*
is a shorthand for ``any number of
a's,''
so
.*
matches any number of anythings.
This is used like this:
s/.*/stuff/
which changes an entire line,
or
s/.*,//
which deletes all characters in the line up to and
including the last comma.
(Since
.*
finds the longest possible match,
this goes up to the last comma.)
[
is used with
]
to form ``character classes'';
for example,
/[0123456789]/
matches any single digit -
any one of the characters inside the braces
will cause a match.
This can be abbreviated to
[0-9].
Finally, the
&
is another shorthand character -
it is used only on the right-hand part of a substitute command
where it means ``whatever was matched on the left-hand side''.
It is used to save typing.
Suppose the current line contained
Now is the time
and you wanted to put parentheses around it.
You could just retype the line, but
this is tedious.
Or you could say
s/^/(/
s/$/)/
using your knowledge of
^
and
$.
But the easiest way uses the
&:
s/.*/(&)/
This says ``match the whole line, and replace it
by itself surrounded by parentheses.''
The
&
can be used several times in a line;
consider
using
s/.*/&? &!!/
to produce
Now is the time? Now is the time!!
You don't have to match the whole line, of course:
if the buffer contains
the end of the world
you could type
/world/s//& is at hand/
to produce
the end of the world is at hand
Observe this expression carefully,
for it illustrates how to take advantage of
ed
to save typing.
The string
/world/
found the desired line;
the shorthand
//
found the same
word in the line;
and the
&
saves you from typing it again.
The
&
is a special character only within
the replacement text of a substitute command,
and has no special meaning elsewhere.
You can turn off the special meaning of
&
by preceding it with a
\:
s/ampersand/\&/
will convert the word ``ampersand'' into the literal symbol
&
in the current line.
The general form of ed commands is the command name, perhaps preceded by one or two line numbers, and, in the case of e, r, and w, followed by a file name. Only one command is allowed per line, but a p command may follow any other command (except for e, r, w and q).
a: Append, that is, add lines to the buffer (at line dot, unless a different line is specified). Appending continues until . is typed on a new line. Dot is set to the last line appended.
c: Change the specified lines to the new text which follows. The new lines are terminated by a ., as with a. If no lines are specified, replace line dot. Dot is set to last line changed.
d: Delete the lines specified. If none are specified, delete line dot. Dot is set to the first undeleted line, unless $ is deleted, in which case dot is set to $.
e: Edit new file. Any previous contents of the buffer are thrown away, so issue a w beforehand.
f: Print remembered filename. If a name follows f the remembered name will be set to it.
g:
The command
g//commands
will execute the commands on those lines that contain
---,
which can be any context search expression.
i: Insert lines before specified line (or dot) until a . is typed on a new line. Dot is set to last line inserted.
m: Move lines specified to after the line named after m. Dot is set to the last line moved.
p: Print specified lines. If none specified, print line dot. A single line number is equivalent to line-number p. A single return prints .+1, the next line.
q: Quit ed. Wipes out all text in buffer if you give it twice in a row without first giving a w command.
r: Read a file into buffer (at end unless specified elsewhere.) Dot set to last line read.
s:
The command
s/string1/string2/
substitutes the characters
string1
into
string2
in the specified lines.
If no lines are specified, make the substitution in line dot.
Dot is set to last line in which a
substitution took place, which means that if no substitution took place, dot is not changed.
s
changes only the first occurrence of
string1
on a line;
to change all of them, type a
g
after the final slash.
v:
The command
v//commands
executes
commands
on those lines that
do not
contain
---.
w: Write out buffer onto a file. Dot is not changed.
.=: Print value of dot. (= by itself prints the value of $.)
!:
The line
!commandline
causes
command-line
to be executed as a
UNIX
command.
/-----/: Context search. Search for next line which contains this string of characters. Print it. Dot is set to the line where string was found. Search starts at .+1, wraps around from $ to 1, and continues to dot, if necessary.
?-----?: Context search in reverse direction. Start search at .-1, scan to 1, wrap around to $.