My goal is to search a 500Gb file for a series of hexadecimal characters and to export the results into a text file. I need to automate this, as there are many patterns to be searched.
The results need to include: the location in the file, the 100 preceding hex characters values (represented in both hex and ascii).
As noted, this is OS agnostic (and language agnostic, if anyone suggests scripts or code).
Related
My output (csv/json) from my newly-created program (using .NET framework 4.6) need to be converted to a IBM-1027-codepage-binary-file (to be imported to Japanese client's IBM mainframe),
I've search the internet and know that Microsoft doesn't have equivalent to IBM-1027 code page.
So how could I output a IBM-1027-codepage-binary-file if I have an UTF-8 CSV/json file in my hand?
I'm asking around for other solutions, but for now, I think I'm going to have to suggest you do the conversion manually; I assume whichever language you're using allows you to do a hex conversion, at worst. For mainframes, the codepage is usually implicit in the dataset, it isn't something that is included in the file header.
So, what you can do is build a conversion table, from https://www.ibm.com/support/knowledgecenter/en/SSEQ5Y_5.9.0/com.ibm.pcomm.doc/reference/html/hcp_reference26.htm. Grab a character from your json/csv file, convert to the appropriate hex digits, and write those hex digits to a file. Repeat until EOF. (Note to actually write the hex data, not the ascii representation of the hex data.) Make sure that when the client transfers the file to their system, they perform a binary transfer.
If you wanted to get more complicated than that, you could look at enhancing/overriding part of the converter to CP500, which does exist on Microsoft Windows. One of the design points for EBCDIC was to make doing character conversions as simple as possible, so many of the CP500 characters hex representations are the same as the CP1027, with the exception of the Kanji characters.
This is a separate answer, from a colleague; I don't have the ability to validate it, I'm afraid.
transfer the file to the host in raw mode, just tag it as ccsid 1208
(edited)
for uss export _BPXK_AUTOCVT=ALL
oedit/obrowse handles it automatically.
I often come across the situation where I would like to read a file's original content in a human-readable way. When opening this kind of file in a text editor, why is it that it is usually gibberish with some complete and comprehensible text ? I would think that if the file is converted to something other than it's original written format, that there would be no comprehensible text remaining, yet I often find it is somewhere in between.
For example, I know that if I open a binary in a text format, there will be nothing comprehensible left that isn't purely accidental.
Example screencapture of partial gibberish text
Why is there complete text in here mixed with gibberish? Does that mean if I open the file with some sort of different encoding (I don't know what's possible), the file will come through as fully readable text? I would understand if it were all-or-nothing (either gibberish-non-readable OR human language) but I don't understand the in-between.
Please provide educational responses, rather than "because that's the way it is" type answers.
Those are formatting characters; there is no standard use and vary by the format of the file in question. You can still extract the text as needed with a fair knowledge of grep and regex, but it won't be fun. The best bet is to open the file with the software that can read it properly, as a text editor like gedit or Notepad++ will read the raw data and display that. Adobe's pdf format has text embedded, for instance, and all that gibberish is instructions for the Reader software for displaying it correctly on the screen while still allowing for relatively straightforward text extraction when required.
Editors have no real way to interpret the special formatting characters, and would need to be loaded with APIs for every conceivable program. They would also need to be updated constantly, since the formatting changes regularly for a variety of reasons. Many times, it is just to keep the files from being backward compatible with their own or other products, forcing an upgrade path. Microsoft is rather famous for that, but they are by far not the only company to do so.
I'm working on a project for school.
The assignment is as follows:
Implement a sorting algorithm of your choosing in assembly (we are using the GNU Assembler). The input is a text-file with a series of numbers separated by newline.
I'm then trying to implement insertion sort.
I have already opened and read the file and i'm able to print the content to terminal.
My problem is now how to split each number from the file in order to compare and sort them.
I believe google is glowing at the moment due to my effort to find and answer (maybe I don't know what I need to type or where to look).
I have tried to get each character from the string, which i'm able to do BUT I don't know to put them together again as integers (we only have integers).
If anybody could help with some keywords to search for it would be much appreciated.
The basic question is, how does notepad (or other basic text editors) store data. I ran into this because I was trying to compare file size of different compression techniques, and realized something isn't quite right.
To elaborate..
If I save a text file with the following contents:
a
The file is 1 byte. This one happens to be 97, or 0x61.
I create a text file with the following contents:
!"#$%&'()*+,-./0123456789:;<=>?#ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~ ¡¢£¤¥¦§¨©ª«¬®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿ
Which is all the characters from 0-255, or 0x00 to 0xFF.
This file is 256 bytes. 1 byte for each character. This makes sense to me.
Then I append the following character to the end of the above string.
†
A character not contained in the above string. All 8 bit characters were already used. This character is 8224, or 0x2020. A 2 bytes character.
And yet, the file size has only changed from 256 to 257 bytes. In fact, the above character saved by itself only shows 1 byte.
What am I missing?
Edit: Please note that in the second text block, many of the characters do not show up on here.
In ANSI encoding (This 8-bit Microsoft-specific encoding), you save each character in one byte (8-bit).
ANSI also called Windows-1252, or Windows Latin-1
You should have a look at ANSI table in ANSI Character Codes Chart or Windows-1252
So for † character, its code is 134, byte 0x86.
Using one byte to encode a character only makes sense on the surface. Works okay if you speak English, it is a fair disaster is you speak Chinese or Japanese. Unicode today has definitions for 110,187 typographic symbols with room to grow up to 1.1 million. A byte is not a good way to store a Unicode symbol since it can encode only 256 distinct values.
Accordingly, text editors must always encode text when they store it to a file. Encoding is required to map 110,187 values onto a byte-oriented storage medium. Inevitably that takes more than 1 byte per character if you speak Chinese.
There have been lots and lots of encoding schemes in common use. Popular in the previous century were code pages, a scheme that uses a character set. A language-specific mapping that tries as hard as it can to need only 1 byte of storage per character by picking 256 characters that are likely to be needed in the language. Japanese, Korean and Chinese used a multi-byte mapping because they had to, other languages used 1.
Code pages have been an enormous disaster, a program cannot properly read a text file that was encoded in another language's code page. It worked when text files stayed close to the machine that created it, the Internet in particular broke that usage. Japanese was particularly prone to this disaster since it had more than one code page in common use. The result is called mojibake, the user looks at gibberish in the text editor. Unicode came around in 1992 to try solve this disaster. One new standard to replace all the other ones, tends to invoke another kind of disaster.
You are subjected to that kind of disaster, particularly if you use Notepad. A program that tries to be compatible with text files that were created in the past 30 years. Google "bush hid the facts" for a hilarious story about that. Note the dialog you get when you use File > Save As, the dialog has an extra combobox titled "Encoding". The default is ANSI, a broken name from the previous century that means "code page". As you found out, that character indeed only needed 1 byte in your machine's default code page. Depends where you live, it is 1252 in Western Europe and the Americas. You'd get 0x86 if you look at the file with a hex viewer.
Given that the dialog gives you a choice and you should not favor ANSI's mojibake anymore, always favor UTF-8 instead. Maybe they'll update Notepad some day so it uses a better default, very hard to do.
For example if I know that ć should be ć, how can I find out the codepage transformation that occurred there?
It would be nice if there was an online site for this, but any tool will do the job. The final goal is to reverse the codepage transformation (with iconv or recode, but tools are not important, I'll take anything that works including python scripts)
EDIT:
Could you please be a little more verbose? You know for certain that some substring should be exactly. Or know just the language? Or just guessing? And the transformation that was applied, was it correct (i.e. it's valid in the other charset)? Or was it single transformation from charset X to Y but the text was actually in Z, so it's now wrong? Or was it a series of such transformations?
Actually, ideally I am looking for a tool that will tell me what happened (or what possibly happened) so I can try to transform it back to proper encoding.
What (I presume) happened in the problem I am trying to fix now is what is described in this answer - utf-8 text file got opened as ascii text file and then exported as csv.
It's extremely hard to do this generally. The main problem is that all the ascii-based encodings (iso-8859-*, dos and windows codepages) use the same range of codepoints, so no particular codepoint or set of codepoints will tell you what codepage the text is in.
There is one encoding that is easy to tell. If it's valid UTF-8, than it's almost certainly no iso-8859-* nor any windows codepage, because while all byte values are valid in them, the chance of valid utf-8 multi-byte sequence appearing in a text in them is almost zero.
Than it depends on which further encodings may can be involved. Valid sequence in Shift-JIS or Big-5 is also unlikely to be valid in any other encoding while telling apart similar encodings like cp1250 and iso-8859-2 requires spell-checking the words that contain the 3 or so characters that differ and seeing which way you get fewer errors.
If you can limit the number of transformation that may have happened, it shouldn't be too hard to put up a python script that will try them out, eliminate the obvious wrongs and uses a spell-checker to pick the most likely. I don't know about any tool that would do it.
The tools like that were quite popular decade ago. But now it's quite rare to see damaged text.
As I know it could be effectively done at least with a particular language. So, if you suggest the text language is Russian, you could collect some statistical information about characters or small groups of characters using a lot of sample texts. E.g. in English language the "th" combination appears more often than "ht".
So, then you could permute different encoding combinations and choose the one which has more probable text statistics.