I'm downloading via FTP some files with chinese names (BIG5 encoded), and Filezilla displays those filenames as garbage (as FTP cannot handle any encoding other than ASCII and UTF-8, as least the standard compliant ones).
Given a filename with garbled characters, is it possible for me to repair the encoding and get a proper filename String given that I already know the source encoding? Will the FTP client misinterpreting BIG5 as UTF-8 insert bytes that make conversion back to BIG5 difficult?
My proposed steps (in Java):
1. get the garbled filename using File object.
2. getbytes using UTF-8.
3. create a new string using those bytes in BIG5.
4. Write the decoded filename back to the file.
Will the above method work?
Not every sequence of bytes is a valid ASCII or UTF-8 string so it's quite likely that some of the bytes will have been discarded, converted to the replacement character, or otherwise irreversibly mangled. So it looks like you won't be able to retrieve the original filenames if they have been modified by FileZilla to become correctly formed UTF-8 or ASCII.
You might be lucky to be able to get a certain percentage of the original characters back, where they just happened to be both valid BIG5 and valid UTF-8, but I doubt you will be able to recover the entire filename.
You could post a few examples of your garbled filenames (as raw bytes encoded in hex) to get a more definite answer. That way we can see exactly what the damage is.
Related
I would like to test some file character encoding detection functionality, where I input files of type UTF-8, windows-1252, ISO-8859-1, etc.
I also want to input files with unknown character encoding so that the user can be alerted.
I haven't found a good way to create files with an unknown or undetectable character encoding.
head -c1024 /dev/random > /tmp/badencoding
This is almost certainly what you want in practice (1kB of random data), but there isn't really a good definition of "undetectable character encoding." This random file is legal 8-bit ASCII. The fact that it certainly is not meant to be 8-bit ASCII is just a heuristic. So all you're going to wind up doing is testing that your algorithm works in ways that your users probably want it to; there is no ultimate "correct" here without reading the mind of the person who created the file.
An empty text file has an undetectable character encoding (except if it has a Unicode BOM).
But basically, you either have to require the user to tell which character encoding a file they are giving you uses, or tell them which one to use (or both, if you specify a default but allow it to be overridden [which is what many compilers do.]).
You can then test the contents for validity against the agreed character encoding. This will catch some errors but note that many character encodings allow any sequence of bytes with any value so any content is always valid (even if the character encoding is not what was used to write the file).
You can then test for consistency with expected values, such as some syntax or allowable character or words, to catch more errors (but you wouldn't necessarily be able to say the character encoding didn't match; it could be just the content is incorrect).
To create files with different character encodings, you could write a program or use a 3rd-party program such as iconv or PowerShell.
If you want an unknown character encoding, just generate a random integer map, convert a file, discard the map, and then not even you will know it.
Ultimately, text files are too technical for users to deal with. Give them some other option such as an open document or spreadsheet format such as .odt, .docx, .ods, or .xlsx. These are very easy to read by programs.
I get text file of random encoding format, usc-2le, ansi, utf-8, usc-2be etc. I have to convert this files to utf8.
For conversion am using the following command
iconv options -f from-encoding -t utf-8 <inputfile > outputfile
But if incorrect from-encoding is provided, then incorrect file is generated.
I want a way to find the input file encoding type.
Thanks in advance
On Linux you could try using file(1) on your unknown input file. Most of the time it would guess the encoding correctly. Or else try several encodings to iconv till you "feel" that the result is acceptable (for example if you know that the file is some Russian poetry, you might try KOI-8, UTF-8, etc.... till you recognize a good Russian poem).
But character encoding is a nightmare and can be ambiguous. The provider of the file should tell you what encoding he used (and there is no way to get that encoding reliably and in all cases : there are some byte sequences which would be valid and interpreted differently with various encodings).
(notice that the HTTP protocol mentions and explicits the encoding)
In 2017, better use UTF-8 everywhere (and you should follow that http://utf8everywhere.org/ link) so ask your human partners to send you UTF-8 (hopefully most of your files are in UTF-8, since today they all should be).
(so encoding is more a social issue than a technical one)
I get text file of random encoding format
Notice that "random encoding" don't exist. You want and need to find out what character encoding (and file format) has been used by the provider of that file (so you mean "unknown encoding", not "random" one).
BTW, do you have a formal, unambiguous, sound and precise definition of text file, beyond file without zero bytes, or files with few control characters? LaTeX, C source, Markdown, SQL, UUencoding, shar, XPM, and HTML files are all text files, but very different ones!
You probably want to expect UTF-8, and you might use the file extension as some hint. Knowing the media-type could help.
(so if HTTP has been used to transfer the file, it is important to keep (and trust) the Content-Type...; read about HTTP headers)
[...] then incorrect file is generated.
How do you know that the resulting file is incorrect? You can only know if you have some expectations about that result (e.g. that it contains Russian poetry, not junk characters; but perhaps these junk characters are some bytecode to some secret interpreter, or some music represented in weird fashion, or encrypted, etc....). Raw files are just sequences of bytes, you need some extra knowledge to use them (even if you know that they use UTF-8).
We do file encoding conversion with
vim -c "set encoding=utf8" -c "set fileencoding=utf8" -c "wq" filename
It's working fine , no need to give source encoding.
I was wondering how Windows interprets characters.
I made a file with a hex editor with the 3 bytes E3 81 81.
Those bytes are the ぁ character in UTF-8.
I opened the notepad and it displayed ぁ. I didn't specify the encoding of the file, I just created the bytes and the notepad interpreted it correctly.
Is notepad somehow guessing the encoding?
Or is the hex editor saving those bytes with a specific encoding?
If the file only contains these three bytes, then there is no information at all about which encoding to use.
A byte is just a byte, and there is no way to include any encoding information in it. Besides, the hex editor doesn't even know that you intended to decode the data as text.
Notepad normally uses ANSI encoding, so if it reads the file as UTF-8 then it has to guess the encoding based on the data in the file.
If you save a file as UTF-8, Notepad will put the BOM (byte order mark) EF BB BF at the beginning of the file.
Notepad makes an educated guess. I don't know the details, but loading the first few kilobytes and trying to convert them from UTF-8 is very simple, so it probably does something similar to that.
...and sometimes it gets it wrong...
https://ychittaranjan.wordpress.com/2006/06/20/buggy-notepad/
There is an easy and efficient way to check whether a file is in UTF-8. See Wikipedia: http://en.wikipedia.org/w/index.php?title=UTF-8&oldid=581360767#Advantages, fourth bullet point. Notepad probably uses this.
Wikipedia claims that Notepad used the IsTextUnicode function, which checks whether a patricular text is written in UTF-16 (it may have stopped using it in Windows Vista, which fixed the "Bush hid the facts" bug): http://en.wikipedia.org/wiki/Bush_hid_the_facts.
how to identify the file is in which encoding ....?
Go to the file and try to Save As... and you can see the default (current) encoding of the file (in which encoding it is saved).
I'm encountering a little problem with my file encodings.
Sadly, as of yet I still am not on good terms with everything where encoding matters; although I have learned plenty since I began using Ruby 1.9.
My problem at hand: I have several files to be processed, which are expected to be in UTF-8 format. But I do not know how to batch convert those files properly; e.g. when in Ruby, I open the file, encode the string to utf8 and save it in another place.
Unfortunately that's not how it is done - the file is still in ANSI.
At least that's what my Notepad++ says.
I find it odd though, because the string was clearly encoded to UTF-8, and I even set the File.open parameter :encoding to 'UTF-8'. My shell is set to CP65001, which I believe also corresponds to UTF-8.
Any suggestions?
Many thanks!
/e: What's more, when in Notepad++, I can convert manually as such:
Selecting everything,
copy,
setting encoding to UTF-8 (here, \x-escape-sequences can be seen)
pasting everything from clipboard
Done! Escape-characters vanish, file can be processed.
Unfortunately that's not how it is done - the file is still in ANSI. At least that's what my Notepad++ says.
UTF-8 was designed to be a superset of ASCII, which means that most of the printable ASCII characters are the same in UTF-8. For this reason it's not possible to distinguish between ASCII and UTF-8 unless you have "special" characters. These special characters are represented using multiple bytes in UTF-8.
It's well possible that your conversion is actually working, but you can double-check by trying your program with special characters.
Also, one of the best utilities for converting between encodings is iconv, which also has ruby bindings.
I have a bunch of files with a mixtures of encodings mainly ISO-8859-1 and UTF-8.
I would like to make all files UTF-8, but when trying to batch encode this files using
iconv some problems arise. (Files cuts by half, etc.)
I supposse the reason is that iconv requires to know the 'from' encoding, so if the command looks like this
iconv -f ISO-8859-1 -t UTF-8 in.php -o out.php
but 'in.php' if already UTF-8 encoded, that causes problems (correct me if I'm wrong)
Is there a way, that I can list all the files whose encoding is not UTF-8?
You can't find files that are definitely ISO-8859-1, but you can find files that are valid UTF-8 (which unlike most multibyte encodings give you a reasonable assurance that they are in fact UTF-8). moreutils has a tool isutf8 which can do this for you. Or you can write your own, it would be fairly simple.
It's often hard to tell just by reading a text file whether it's in UTF-8 encoding or not. You could scan the file for certain indicator bytes which can never occur in UTF-8, and if you find them, you know the file is in ISO-8859-1. If you find a byte with its high-order bit set, where the bytes both immediately before and immediately after it don't have their high-order bit set, you know it's ISO encoded (because bytes >127 always occur in sequences in UTF-8). Beyond that, it's basically guesswork - you'll have to look at the sequences of bytes with that high bit set and see whether it would make sense for them to occur in ISO-8859-1 or not.
The file program will make an attempt to guess the encoding of a text file it's processing, you could try that.
with find it's quite simple
find . -print0 | xargs -0 file | grep 8859
Is there a way, that I can list all the files whose encoding is not UTF-8?
Perhaps not so easily in bash alone, but it's a trivial task from eg. Python:
import os.path
for child in os.path.listdir(TARGETDIR):
child= os.path.join(TARGETDIR, child)
if os.path.isfile(child):
content= open(child, 'rb').read()
try:
unicode(content, 'utf-8')
except UnicodeDecodeError:
open(child, 'wb').write(unicode(content, 'iso-8859-1'))
This assumes that any file that can be interpreted as a valid UTF-8 sequence is one (and so can be left alone), whilst anything that isn't must be ISO-8859-1.
This is a reasonable assumption if those two are the only possible encodings, because valid UTF-8 sequences (of at least two top-bit-set characters in a particular order) are relatively rare in real Latin text, where we tend only to use the odd single accented characters here and there.
What kind of content? XML? Then yes, if properly tagged at the top. Generic text files? I don't know of any a-priori way to know what encoding is used, although it might be possible, sometimes, with clever code. "Tagged" UTF-8 text files, by which I mean UTF-8 text files with a Byte-Order mark? (For UTF-8, the three byte sequence "") Probably. The Byte Order Mark characters will not commonly appear as the first three characters in a ISO-8859-1 encoded file. (Which bobince pointed out in a comment to this post, so I'm correcting my post.)
For your purposes, tools exist that can probably solve most of your question. Logan Capaldo pointed out one in his answer.
But after all, if it were always possible to figure out, unambiguously, what character encoding was used in a file, then the iconv utility wouldn't need you to provide the "from" encoding. :)