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*10.2* Substitution *find-replace*
The ":substitute" command enables you to perform string replacements on a
whole range of lines. The general form of this command is as follows:
:[range]substitute/from/to/[flags]
This command changes the "from" string to the "to" string in the lines
specified with [range]. For example, you can change "Professor" to "Teacher"
in all lines with the following command:
:%substitute/Professor/Teacher/
Note:
The ":substitute" command is almost never spelled out completely.
Most of the time, people use the abbreviated version ":s". From here
on the abbreviation will be used.
The "%" before the command specifies the command works on all lines. Without
a range, ":s" only works on the current line. More about ranges in the next
section |10.3|.
By default, the ":substitute" command changes only the first occurrence on
each line. For example, the preceding command changes the line:
Professor Smith criticized Professor Johnson today.
to:
Teacher Smith criticized Professor Johnson today.
To change every occurrence on the line, you need to add the g (global) flag.
The command:
:%s/Professor/Teacher/g
results in (starting with the original line):
Teacher Smith criticized Teacher Johnson today.
Other flags include p (print), which causes the ":substitute" command to print
out each line it changes. The c (confirm) flag tells ":substitute" to ask you
for confirmation before it performs each substitution. Enter the following:
:%s/Professor/Teacher/c
Vim finds the first occurrence of "Professor" and displays the text it is
about to change. You get the following prompt:
replace with Teacher (y/n/a/q/l/^E/^Y)?
At this point, you must enter one of the following answers:
y Yes; make this change.
n No; skip this match.
a All; make this change and all remaining ones without
further confirmation.
q Quit; don’t make any more changes.
l Last; make this change and then quit.
CTRL-E Scroll the text one line up.
CTRL-Y Scroll the text one line down.
The "from" part of the substitute command is actually a pattern. The same
kind as used for the search command. For example, this command only
substitutes "the" when it appears at the start of a line:
:s/^the/these/
If you are substituting with a "from" or "to" part that includes a slash, you
need to put a backslash before it. A simpler way is to use another character
instead of the slash. A plus, for example:
:s+one/two+one or two+
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The ":substitute" command, and many other : commands, can be applied to a
selection of lines. This is called a range.
The simple form of a range is {number},{number}. For example:
:1,5s/this/that/g
Executes the substitute command on the lines 1 to 5. Line 5 is included.
The range is always placed before the command.
A single number can be used to address one specific line:
:54s/President/Fool/
Some commands work on the whole file when you do not specify a range. To make
them work on the current line the "." address is used. The ":write" command
works like that. Without a range, it writes the whole file. To make it write
only the current line into a file:
:.write otherfile
The first line always has number one. How about the last line? The "$"
character is used for this. For example, to substitute in the lines from the
cursor to the end:
:.,$s/yes/no/
The "%" range that we used before, is actually a short way to say "1,$", from
the first to the last line.
USING A PATTERN IN A RANGE
Suppose you are editing a chapter in a book, and want to replace all
occurrences of "grey" with "gray". But only in this chapter, not in the next
one. You know that only chapter boundaries have the word "Chapter" in the
first column. This command will work then:
:?^Chapter?,/^Chapter/s=grey=gray=g
You can see a search pattern is used twice. The first "?^Chapter?" finds the
line above the current position that matches this pattern. Thus the ?pattern?
range is used to search backwards. Similarly, "/^Chapter/" is used to search
forward for the start of the next chapter.
To avoid confusion with the slashes, the "=" character was used in the
substitute command here. A slash or another character would have worked as
well.
ADD AND SUBTRACT
There is a slight error in the above command: If the title of the next chapter
had included "grey" it would be replaced as well. Maybe that’s what you
wanted, but what if you didn’t? Then you can specify an offset.
To search for a pattern and then use the line above it:
/Chapter/-1
You can use any number instead of the 1. To address the second line below the
match:
/Chapter/+2
The offsets can also be used with the other items in a range. Look at this
one:
:.+3,$-5
This specifies the range that starts three lines below the cursor and ends
five lines before the last line in the file.
USING MARKS
Instead of figuring out the line numbers of certain positions, remembering them
and typing them in a range, you can use marks.
Place the marks as mentioned in chapter 3. For example, use "mt" to mark
the top of an area and "mb" to mark the bottom. Then you can use this range
to specify the lines between the marks (including the lines with the marks):
:’t,’b
VISUAL MODE AND RANGES
You can select text with Visual mode. If you then press ":" to start a colon
command, you will see this:
:'<,’>
Now you can type the command and it will be applied to the range of lines that
was visually selected.
Note:
When using Visual mode to select part of a line, or using CTRL-V to
select a block of text, the colon commands will still apply to whole
lines. This might change in a future version of Vim.
The ‘< and ‘> are actually marks, placed at the start and end of the Visual
selection. The marks remain at their position until another Visual selection
is made. Thus you can use the "‘<" command to jump to position where the
Visual area started. And you can mix the marks with other items:
:’>,$
This addresses the lines from the end of the Visual area to the end of the
file.
A NUMBER OF LINES
When you know how many lines you want to change, you can type the number and
then ":". For example, when you type "5:", you will get:
:.,.+4
Now you can type the command you want to use. It will use the range "."
(current line) until ".+4" (four lines down). Thus it spans five lines.
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