vim and unrecognized characters - vim

I have a file with some accents, and VIM displays them as "~V" characters. The "od -bc" command tells me the characters are charcode 226. I want to substitute them using VIM. But I can't get it to match the characters. How can I achieve that?
Optional question: how can I have VIM tell me which charset is used to interpret the current file?

You can use the following formats, from vim's manual on patterns and regular expressions:
ordinary atom
magic nomagic matches
\%d \%d match specified decimal character (eg \%d123
\%x \%x match specified hex character (eg \%x2a)
\%o \%o match specified octal character (eg \%o040)
\%u \%u match specified multibyte character (eg \%u20ac)
\%U \%U match specified large multibyte character (eg \%U12345678)
So you should be able to do something like this to replace char 226 with a space globally in the file:
:%s/\%d226/ /g
As for the latter, if you do:
:set encoding
You'll see output like:
encoding=latin1

One very simple way to deal with such "weird" characters is:
select the offending character(s) visually (v)
yank it to buffer
replace it with: :%s/<ctrl-r>"/something-else/g
where <ctrl-r> is pressing ctrl and letter r - together with " it will copy buffer to command line - effectively putting your offending characters inside of s/// operation.

Related

how to remove specific characters in vi or vim editor

I have some txt in vi:
|NC_004718|29751nt|SARS
|NC_045512|29903nt|Severe
|NC_004718|29751nt|SARS
|NC_045512|29903nt|Severe
|NC_004718|29751nt|SARS
now I want to replace remove everything after NC_004718, my expected output is:
NC_004718
NC_045512
NC_004718
NC_045512
NC_004718
How to do it? Thanks.
I would recommend using a substitution with regular expression to match the entire string and to capture what you would like to keep in parentheses. That way you can then replace the entire string with just the match.
:%s/^|\([^|]\+\)|.\+/\1/
To break down what is happening:
% means that you want to apply the command to each line within the file.
s means that you are doing substitution command (on each line). The s command has a syntax of s/<regular expression pattern>/<replacement>/<flags>
The regular eression pattern in the above command is ^|\([^|]\+\)|.\+.
^ means match from the line start.
| matches the character |.
\([^|]\+\) matches all characters except for the character |. Note that the real regular expression is actually ([^|]+), the additional \ characters are there because Vim needs to know that they are intended to be special characters for processing and not exact characters it needs to match. Also note that the parentheses are there to capture the match into a group (see below).
| again matches the actual character |.
.\+ matches all characters until the end of the line. Note that the . is considered special character by default but + still needs a preceding \.
The replacement text is only \1. This denotes that Vim should replace the text with whatever was captured in the first group (i.e. the first set of parentheses).
There are no flags with this command so there is nothing after the last /.
For example,
:g/NC_\d\+/normal! ygnV]p
:g/regex/ to match lines
normal! to execute Normal mode commands
ygn to yank the text previously matched by :g
V to select the whole line
]p or p to replace the line with the match
If you have only lines like those you have shown try:
:%norm xf|D

How to replace bytes \xe3\x80\x80 with byte \x20 in vim?

Let's to create target file to operate with.
python3
>>> mfile = open("f:/test.txt","wb")
>>> mfile.write(b'\xe3\x80\x80')
3
>>> mfile.close()
Now to open f:/test.txt with xxd,you will see three bytes \xe3\x80\x80 in it,our target file encoding with utf-8 contains three bytes \xe3\x80\x80.
python3
b'\xe3\x80\x80'.decode('utf-8')
'\u3000'
It means that the unicode of three bytes in test.txt encoding with utf-8 is 3000.
:s/\%u3000/ /g
s/\%u3000/ /g can replace bytes \xe3\x80\x80 with byte \x20 in vim.
Issue remains still here.
:s/\%u3000/\%u20/g
:s/\%u3000/\%x20/g
:s/\%u3000/\x20/g
All the three formats above here can't work,why \xe3\x80\x80 can be expressed by \%u3000 in vim, (white blank) can't be expressed by \%u20 or \%x20 or \x20 ?
can express \x20, white blank is printable character,what's more, i want to replace the three bytes \xe3\x80\x80 with latin-1's nbsp?
The nbsp in latin-1 encoding means Non-breaking space which is NON PRINTABLE CHARACTERS,how to write the expression in vim?
:s/\%u3000/\%ua0/g
:s/\%u3000/\%xa0/g
:s/\%u3000/\xa0/g
None of them can work for the case.
You can type the \xe3\x80\x80 or u3000 character by pressing ctrl+v then u and then the 4 Unicode characters, in your case 3000 (check :help i_CTRL-V_digit ), since is a black character you will see nothing but just a space, you could type :set list to see all the places where you have that character or in any case add this to your .vimrc
set listchars=tab:▸\ ,eol:¬,trail:·,extends:#,nbsp:.
Now in the same way you enter the character, you could try to replace it within the command line, but in this case to be available to enter the ctrl+v you could try using the command-line window (:help cedit).
Go to command mode and after having the : press ctrl+f it will open the command-line window in where you could go into insert mode and type: %s/ctrl+vu3000/ /g and when done press enter to apply command.
Give a try first before entering the command-line window, since when using ctrl+v it may work, not like when using ctrl+k (http://vim.wikia.com/wiki/Entering_special_characters)
In the image instead of replacing with a white space / /, Is replacing with ---- just to visually see the changes.
1.How to input non printable characters when to edit a file in vim?
In the insert mode:
1.ctrl+v (ctrl+q if ctrl+v call paste from regitor)
2.input u
3.input the unicode value of non printable characters
4.input enter key
2.How to input non printable characters in substitute command of vim's ex mode?
For example, to replace all bytes \xe3\x80\x80 with \xa0,all byte's encoding is utf-8.
1. get the byte's unicode value
`\xe3\x80\x80`'s unicode value is `3000`,
`\xa0`'s unicode value is `a0`.
2.press `:` into ex mode.
3.:s/\%u3000/
4:ctrl+v ua0
do not input enter as above process
5.go on to input `/g`.
6.press enter.

How to fine-tune Macros after having recorded it through recording in Vim?

Specific question
Description
After recording the desired action to registrar o, I pasted the whole macro to my ~/.vimrc and assigned it as follows (directly pasting the mappings are not displayed properly)
Expected behavior
I would like to use this macro to get myself a new "comment line" that leads a new section of script, formatted such that the name of the section is centered. After populating the "section title", I would like to enter insert mode in a new line.
In the following screen-record, I have tested both #o and #p$ on the word "time". The second attempt with#p` worked as desired.
The problem (on Windows machine specifically)
As you see, the #o mapping gets me junk phrases which had been part of my definition for the macro. Does this have to do with the ^M operator? And, how can I fix the #o mapping, which uses * to populate the line?
The two mapping worked just fine on Linux system. (Don't know why, as I have recorded and pasted the macro-definition on Windows machine.) This also does not appear to be a problem on Mac with MacVim.
Generalized question
Is there a way to properly substitute the ^M operator (for <CR>, or "Enter"-key)?
Is there a way to properly substitute the ^[ operator (for <ESC>, or the "Escape"-key)?
Is there a systematic list of mappings from these weird representation of keystrokes, as recorded by the "recording" function through q.
Solution
Substitute the ^M marks in the macro-definition with \r. And, substitute ^[ to be \x1b, for the ESC key. The mappings are fixed as follows:
let #o = ":center\ri\r\x1bkV:s/ /\*/g\rJx50A\*\x1b80d|o"
let #p = ":center\ri\r\x1bkV:s/ /\"/g\rJx50A\"\x1b80d|o"
Complete list of key-codes/mappings? Approach 1: through hex code.
Thanks to Zbynek Vyskovsky, the picture is clear. For whatever key one may think of, Vim takes its ASCII value at the "face value". (The trick is to use a escape clause starting with \x, where x serves as the leader key/string/character connecting to the hex values.) Thus, the correspondence list (incomplete yet), goes as follows:
Enter --- \x0d --- \r
ESC --- \x1b --- \e
Solution native to Vim
By chance, :help expr-quote gives the following list of special characters. This shall serve as the definite answer to the original question in general form.
string *string* *String* *expr-string* *E114*
------
"string" string constant *expr-quote*
Note that double quotes are used.
A string constant accepts these special characters:
\... three-digit octal number (e.g., "\316")
\.. two-digit octal number (must be followed by non-digit)
\. one-digit octal number (must be followed by non-digit)
\x.. byte specified with two hex numbers (e.g., "\x1f")
\x. byte specified with one hex number (must be followed by non-hex char)
\X.. same as \x..
\X. same as \x.
\u.... character specified with up to 4 hex numbers, stored according to the
current value of 'encoding' (e.g., "\u02a4")
\U.... same as \u but allows up to 8 hex numbers.
\b backspace <BS>
\e escape <Esc>
\f formfeed <FF>
\n newline <NL>
\r return <CR>
\t tab <Tab>
\\ backslash
\" double quote
\<xxx> Special key named "xxx". e.g. "\<C-W>" for CTRL-W. This is for use
in mappings, the 0x80 byte is escaped.
To use the double quote character it must be escaped: "<M-\">".
Don't use <Char-xxxx> to get a utf-8 character, use \uxxxx as
mentioned above.
Note that "\xff" is stored as the byte 255, which may be invalid in some
encodings. Use "\u00ff" to store character 255 according to the current value
of 'encoding'.
Note that "\000" and "\x00" force the end of the string.
As you use assigning to register using vim expression language, it's definitely possible in platform independent way. The strings in vim expressions understand the standard escape sequences, therefore it's best to replace ^M with \r and Esc with \x1b:
let #o = ":center\riSomeInsertedString\x1b"
There is no list of of special characters to be translated as far as I know but you can simply take all control characters (ASCII below 32) and translate them to corresponding escape sequence "\xHexValue" where HexValue is the value of the character. Even \r (or ^M) can be translated to \x0d as its ASCII value is 13 (0x0d hex).

Removing hex code ffa3 in Vim

I've got a file with a load of weird characters with in it that I need to get rid of.
Using ga on the character reveals it has the following encodings:
ᆪ> 65443, Hex ffa3, Octal 177643
But I can't seem to find it using :%s/\%xffa3//g. What am I doing wrong?
Look at :help \%x:
\%x2a Matches the character specified with up to two hexadecimal characters.
So Vim is actually matching the three characters <uf>a3. Since you have a four-digit hex number, you need to use \%u:
:%s/\%uffa3//g
Alternatives
You can also insert the character directly into the command line via :help i_CTRL-V_digit (i.e. <C-v>uffa3), but if you already have instances of that character in your buffer (and near your cursor!), I'd just yank that char with yl and insert it in the command-line via <C-r>".

How to search and replace an unprintable character

I've a file that was exported from Word and it replaced all quotes with strange unicode characters which aren't correctly displayed in vim.
So now I want those characters to be replaced with quotes, but I don't know how to enter this character in
:%s/???/'/g
The characters look like this: ~U ~R. But of course I can't just mark them with mouse and paste in the command.
You can try setting the encoding type and see if it fixes the visalizations of those characters:
:set encoding=utf-8
then you can use them directly. Alternatively, you can place your cursor on the unprintable character and hit ga, it will show the decimal/hex/octal code of that character, then you can substitute it with:
:%s/\%xYY/substitute/g
where YY is the hex code of the char, if it's multibyte:
:%s/\%uYYYY/substitute/g
for details:
:help character-classes
Note that you can search and match with \%xff or \%uabcd but will be unable to substitute with it.
I usually:
delete the character with: x
undo my change with: u
do the substitute thanks to c_CTRL-R: :%s/^R"/'/g
you can also filter it by using the tr command
for example replacing the hex a0 which stems from MacOs cut-and-paste
can be replaced with a whitespace as follows (\240 being the octal representation of hex a0)
:.,$!tr "\240" " "

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