In Vim is it possible to delete lines that has only one letter?
For example
This
is
an
x
z
example
c
would turn into
This
is
an
example
:g/^.$/d
: — switch to the command line;
g — run a global command over all lines;
/^.$/ — find a line that has exactly one character; beginning of the line, any character, end of the line;
d — delete the line.
Related
I am trying to clean up some code and I am trying to find a good way of achieving the following:
I am a #decent
guy
and I want:
I am a guy
I tried using
:g/#/d
but the whole line gets deleted and I only want to delete until the end of line. What is the best way to achieve this in vim?
Thank you.
That won't because the usage of that command:
:[range]g/pattern/cmd
defaults to range being the whole line, and you are not doing any substitution anyway.
Use:
:%s/#.\+\n//g
instead.
# Matches a literal #.
.\+\n Matches everything until the end of line, and a new line.
// Replaces the entire match with nothing.
With :global you would want something like
:global/#/normal! f#D | join
or
:global/#/substitute/#.*// | join
Try this instead:
:s/ # .*\n/ /
Explanation:
You were using the wrong command, as they may look similar to new users.
:[range]g/VRE/act Globally apply the "act"ion (one letter command) to all lines (in range, default all file) matching the VRE (pattern)
:[range]s/VRE/repl/f Substitute within lines (in range, default current line) the matching VRE (pattern) with the "repl"acement using optional "f"lags
Now about the pattern, I think this candidate cover most cases (all but comments at the beginning of a line and comments without space after pound sign)
# litteral space, then hash tag, then space again
.* dot for any character, star to mean the previous may occur many times or even be absent
$ dollar at end to stay at "end of line", but \n to catch en EOL here
press d + shift 4 or d + $, which means delete to end of the line
d means delete
shift 4 or $ means cursor to end of the line
I want to understand what gets stored in Vim's dot(.) register.
Consider the following text:
This is Line one
This is Line two
This is Line three
With the cursor on the first line, if I do A;<esc> I can repeat the same action for the next line by j.
However, if I do the action like removing the last character on the first line by $x and then try to repeat it for the next line by j., it is not removing the last character of the line, instead it just deletes the character under the cursor.
So why is dot command able to remember the position in the first example A;<esc> whereas not able to do the same for $x ?
From :help .:
. Repeat last change, with count replaced with [count].
Also repeat a yank command, when the 'y' flag is
included in 'cpoptions'. Does not repeat a
command-line command.
With A;, the change is to insert a ; at the end of the current line. A moves the cursor and switches to insert mode.
With $x, the $ first moves the cursor, then the x command deletes a character. They are not linked together, so the change is only the deletion of the character at the current cursor position.
(Put another way, the motion is only part of the change if the command takes a motion operator after the command, like d, or if the motion is implicit in the command, like with A.)
I am pretty new to vim and ex and I was wondering if anyone could help me with an area I am fuzzy on. I would like to know how to swap characters on every line or occurrence of a pattern. For example How would I swap the first 2 characters of every line in a file. I know it can be done and I'm pretty sure it involves the use of parentheses to store the chars. But thats is all I know. Also, Say I wanted to replace the 2nd char on everyline with some string, how would I do that?
To replace second character in each line to r in vim: :%s/^\(.\)./\1r/:
:%s/p/r/ replace pattern p with r for all lines (because of %);
^ start line;
\( start a group;
. any character (the first in this example);
\) end the group;
. any character (the second in this example);
\1 back reference to the first group (the first character in this example);
r replacement text.
To swap two first characters: :%s/^\(.\)\(.\)/\2\1/.
Swapping the first two characters on every line:
:%s/^\(.\)\(.\)/\2\1/g
Replacing the second character on every line with "string":
:%s/^\(.\)\(.\)/\1string/g
More info on the substitute command: http://vim.wikia.com/wiki/Search_and_replace
You can do the following to swap the two first chars of every line in the buffer:
:%norm xp
or:
:%s/\v^(.)(.)/\2\1
You'll need the :global command to apply the commands above on every line matching a specific pattern:
:g/foo/norm xp
or:
:g/foo/s/\v^(.)(.)/\2\1
Reference:
:help :normal
:help :global
:help :s
:help range
Suppose I'm editing the following document (* = cursor):
Lions
Tigers
Kittens
Puppies
*
Humans
What sequence can I use to delete the surrounding white space so that I'm left with:
Lions
Tigers
Kittens
Puppies
*
Humans
Note: I'm looking for an answer that handles any number of empty lines, not just this exact case.
EDIT 1: Line numbers are unknown and I only want to effect the span my cursor is in.
EDIT 2: Edited example to show I need to preserve leading whitespace on edges
Thanks
Easy. In normal mode, dipO<Esc> should do it.
Explanation:
dip on a blank line deletes it and all adjacent blank lines.
O<Esc> opens a new empty line, then goes back to normal mode.
Even more concise, cip<Esc> would roll these two steps into one, as suggested by #Lorkenpeist.
A possible solution is to use the :join command with a range:
:?.?+1,/./-1join!
Explanation:
[range]join! will join together a [range] of lines. The ! means with out inserting any extra space.
The starting point is to search backwards to the first character then down 1 line, ?.?+1
As the 1 in +1 can be assumed this can be abbreviated ?.?+
The ending point is to search forwards to the next character then up 1 line, /./-1
Same as before the 1 can be assumed so, /./-
As we are using the same pattern only searching forward the pattern can be omitted. //-
The command :join can be shorted to just :j
Final shortened command:
:?.?+,//-j!
Here are some related commands that might be handy:
1) to delete all empty lines:
:g/^$/d
:v/./d
2) Squeeze all empty lines into just 1 empty line:
:v/./,//-j
For more help see:
:h :j
:h [range]
:h :g
:h :v
Short Answer: ()V)kc<esc>
In normal mode, if you type () your cursor will move to the first blank line. ( moves the cursor to the beginning of the previous block of non-blank lines, and ) moves the cursor to the end (specifically, to the first blank line after said block). Then a simple d) will delete all text until the beginning of the next non-blank line. So the complete sequence is ()d).
EDIT: You're right, that deletes the whitespace at the beginning of the next non-blank line. Instead of d) try V)kd. V puts you in visual line mode, ) jumps to the first non-blank line (skipping the whitespace at the beginning of the line), k moves the cursor up one line. At this point you've selected all the blank lines, so d deletes the selection.
Finally, type O (capital O) followed by escape to crate a new blank line to replace the ones you deleted. Alternatively, replacing dO<Escape> with c<Escape> does the same thing with one less keystroke, so the entire sequence would be ()V)kc<Esc>.
These answers are irrelevant after the updated question:
This may not be the answer you want to hear, but I would make use of ranges. Take a look at the line number for the first empty line (let's say 55 for example) and the second to last empty line (perhaps 67). Then just do :55,67d.
Or, perhaps you only want there to ever be one empty line in your whole file. In that case you can match any occurrence of one or more empty lines and replace them with one empty line.
:%s/\(^$\n\)\+/\r/
This answer works:
If you just want to use normal mode you could search for the last line with something on it. For instance,
/.<Enter>kkVNjd
I didn't test so much, but it should work for your examples. There maybe more elegant solutions.
function! DelWrapLines()
while match(getline('.'),'^\s*$')>=0
exe 'normal kJ'
endwhile
exe 'silent +|+,/./-1d|noh'
exe 'normal k'
endfunction
source it and try :call DelWrapLines()
I know this question has already been resolved, but I just found a great solution in "sed & awk, 2nd Ed." (O'Reilly) that I thought was worth sharing. It does not use vim at all, but instead uses sed. This script will replace all instances of one or more blank lines (assuming there is no whitespace in those lines) with a single blank line. On the command line:
sed '/ˆ$/{
N
/ˆ\n$/D
}' myfile
Keep in mind that sed does not actually edit the file, but instead prints the edited lines to standard output. You can redirect this input to a file:
sed '/ˆ$/{
N
/ˆ\n$/D
}' myfile > tempfile
Be careful though, if you try to write it directly to myfile, it will just delete the entire contents of the file, which is clearly not what you want! After you write the output to tempfile, you can just mv tempfile myfile and tada! All instances of multiple blank lines are replaced by a single blank line.
Even better:
cat -s myfile > temp
mv temp myfile
cat is awesome, yes?
Bestest:
If you want to do it inside vim, you can replace all instances of multiple blank lines with a single blank line by using vim's handy feature of executing shell commands on a range of lines within vim.
:%!cat -s
That's all it takes, and your entire file is reformatted all nice!
In vim when my cursor is on the first line I can press:
100dd
to delete the first 100 lines.
But how do I delete all lines except the last 100 lines?
In normal mode:
G100kdgg
In other words:
G -> go to last line
100k -> go up 100 lines
dgg -> delete to top of file
In ex mode:
:1,$-100d
Explanation: ":" puts the editor in "ex mode". The d command of ex mode deletes lines, specified as a single line number, or a range of lines. $ is the last line, and arithmetic can be applied to line numbers.
An alternative general purpose solution:
:%!tail -100
You can use any shell command after the ! to arbitrarily modify the current buffer. Vim starts the command and feeds the current file to stdin, and reads the new buffer from stdout.