On my Windows 10 PC LabVIEW 2017 is installed. A file I created in LabVIEW 2016 at my Uni will not be opened. When I doubleklick, LabVIEW starts normally, but only as if I had opened it without any file. If I start LabVIEW normally and try to open the file out of the program, nothing will happen, not even an error will occur. Why is this?
Note: Right now I am using LabVIEW 2017 in Evaluation-Mode.
Technically, I think the answer is that ASCII 26 is not a valid character for a Windows path or filename, per the following: https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx
Use any character in the current code page for a name, including
Unicode characters and characters in the extended character set
(128–255), except for the following:
The following reserved characters:
< (less than)
> (greater than)
: (colon)
" (double quote)
/ (forward slash)
\ (backslash)
| (vertical bar or pipe)
? (question mark)
* (asterisk)
Integer value zero, sometimes referred to as the ASCII NUL character.
Characters whose integer representations are in the range from 1
through 31, except for alternate data streams where these characters
are allowed. For more information about file streams, see File
Streams.
Any other character that the target file system does not allow.
(Emphasis mine.)
I found the reason... The file was saved in a subfolder of a folder which name contained a right arrow (→) which is not supported by LabVIEW obviousely...
Related
I cant think of an OS (Linux, Windows, Unix) where this would cause an issue but maybe someone here can tell me if this approach is undesirable.
I would like to use a base64 encoded string as a filename. Something like gH9JZDP3+UEXeZz3+ng7Lw==. Is this likely to cause issues anywhere?
Edit: I will likely keep this to a max of 24 characters
Edit: It looks like I have a character that will cause issues. My function that generated my string is providing stings like: J2db3/pULejEdNiB+wZRow==
You will notice that this has a / which is going to cause issues.
According to this site the / is a valid base64 character so I will not be able to use a base64 encoded string for a filename.
No. You can not use a base64 encoded string for a filename. This is because the / character is valid for base64 strings which will cause issues with file systems.
https://base64.guru/learn/base64-characters
Alternatives:
You could use base64 and then replace unwanted characters but a better option would be to hex encode your original string using a function like bin2hex().
The official RFC 4648 states:
An alternative alphabet has been suggested that would use "~" as the 63rd character. Since the "~" character has special meaning in some file system environments, the encoding described in this section is recommended instead. The remaining unreserved URI character is ".", but some file system environments do not permit multiple "." in a filename, thus making the "." character unattractive as well.
I also found on the serverfault stackexchange I found this:
There is no such thing as a "Unix" filesystem. Nor a "Windows" filesystem come to that. Do you mean NTFS, FAT16, FAT32, ext2, ext3, ext4, etc. Each have their own limitations on valid characters in names.
Also, your question title and question refer to two totally different concepts? Do you want to know about the subset of legal characters, or do you want to know what wildcard characters can be used in both systems?
http://en.wikipedia.org/wiki/Ext3 states "all bytes except NULL and '/'" are allowed in filenames.
http://msdn.microsoft.com/en-us/library/aa365247(VS.85).aspx describes the generic case for valid filenames "regardless of the filesystem". In particular, the following characters are reserved < > : " / \ | ? *
Windows also places restrictions on not using device names for files: CON, PRN, AUX, NUL, COM1, COM2, COM3, etc.
Most commands in Windows and Unix based operating systems accept * as a wildcard. Windows accepts % as a single char wildcards, whereas shells for Unix systems use ? as single char wildcard.
And this other one:
Base64 only contains A–Z, a–z, 0–9, +, / and =. So the list of characters not to be used is: all possible characters minus the ones mentioned above.
For special purposes . and _ are possible, too.
Which means that instead of the standard / base64 character, you should use _ or .; both on UNIX and Windows.
Many programming languages allow you to replace all / with _ or ., as it's only a single character and can be accomplished with a simple loop.
In Windows, you should be fine as long if you conform to the naming conventions of Windows:
https://learn.microsoft.com/en-us/windows/win32/fileio/naming-a-file#naming-conventions.
As far a I know, any base64 encoded string does not contain any of the reserves characters.
The thing that is probably going to be a problem is the lengte of the file name.
Informix 11.5
I am trying to search for carriage returns and line feeds that may exist in a VARCHAR field. First, I need a SELECT statement to show that they exist. Second, I need to REPLACE them with a space or other character.
I've tried all kinds of variations:
CHR(10) + CHR(13)
CHR(10) || CHR(13)
CHAR(13) + CHAR(10)
CHAR(13) || CHAR(10)
SELECT CHR(10) from systables;
Everything gives an error: Routine (chr) can not be resolved.
I've been searching all over and just can't find anything that works, and I'm sure this is crazy stupid easy.
Get the ASCII package from the IIUG
The CHR() function was added to IDS 11.70; it isn't in IDS 11.50.
The good news is you can add the function because IDS is an extensible server. The better news for you is that you can obtain the relevant code from the IIUG web site in the Software Archive under the Miscellaneous section as ascii.
That should allow you to do what you need. (Note: I wrote the code way back when — before there was support built into any of the servers.)
Windows makes things more complicated
I was uploading the ascii.unl file and I get an error that the number of columns do not match on line 13. Have you seen this before? I'm on Windows 2008. The errors are:
846: Number of values in load file is not equal to number of columns.
847: Error in load file line 13.
I hadn't seen it before, but I've not tried the file on Windows and … well, let's say life gets trickier on Windows than it is on Unix (and this bit isn't all that simple on Unix).
First of all, the data file needs to have CRLF line endings instead of the NL-only line endings that are standard on Unix. (Note that NL, newline, is another name for LF, line feed — aka '\n'.) For most lines in the unload file, that isn't a problem.
The two entries for which it might be (is) a problem are for CR and LF — entries 13 and 10 respectively. In theory, if the entry for line 10 contains (in C string notation) "10|\\\n\r\n" (that is, 10, pipe, backslash, newline, CRLF), all should be OK; the absence of an error message for line 10 suggests that it is OK.
Similarly, the entry for line 13 is "13|\r\r\n", which apparently causes grief. The simplest trial fix is to add a backslash here too: "13|\\\r\r\nn". The backslash says "the next character doesn't have a special meaning". If that doesn't work, we'll probably have to try hex-escape notation: "13|\\0d\r\n" — and use dbaccess -X to enable the hex escape notation.
With luck, one of those two (or both) will work. If neither works, come back and we'll try to think of something else.
As per my above comment:
I was uploading the ascii.unl file and I get an error that the number of columns do not match on line 13. Have you seen this before? I'm on Windows 2008. 846: Number of values in load file is not equal to number of columns. 847: Error in load file line 13.
Here is what I see in the ascii.unl file.
If I put this into MS Word and turn on Show Formatting/Paragraph marks, it shows this:
Example:
Open "C:\...\someFile.txt" For Output As #1
Print #1, someString
Close #1
If someString contains non-ASCII characters, how are they encoded? (UTF-8, Latin-1, some codepage depending on the Windows locale, ...)
On my system, the code above seems to use Windows-1252, but since neither the documentation of the Open statement nor the documentation of the Print # statement mention string encodings, I cannot be sure whether this is some built-in default or some system setting, and I'm looking for an authorative answer.
Note: Thanks to everyone suggesting alternatives for how to create files with specific encodings (ADODB.Stream, Scripting.FileSystemObject, etc.) - they are appreciated. This question, however, is about understanding the exact behavior of legacy code, so I am only interested in the behavior of the code quoted above.
Testing indicates that the VBA Print command converts Unicode strings to the single-byte character set of the code page for the current Windows "Language for non-Unicode programs" system locale. This can be illustrated with the following code, which attempts to write the Greek word Ώπα:
Option Compare Database
Option Explicit
Sub GreekTest()
Dim someString As String
someString = ChrW(&H38F) & ChrW(&H3C0) & ChrW(&H3B1)
Open "C:\Users\Gord\Desktop\someFile.txt" For Output As #1
Print #1, someString
Close #1
End Sub
When run with Windows set to the default locale for US English, the resulting file contains the bytes
3F 70 61
which correspond to the Windows-1252 characters ?pa. Windows-1252 is the character set most commonly (but incorrectly) referred to as "ANSI".
However, after changing the Windows "non-Unicode" locale setting to Greek (Greece)
the same VBA code writes a file containing the bytes
BF F0 E1
which correspond to the Windows-1253 (Greek) characters Ώπα.
I'm trying to teach myself basics of GNU Radio and DSP. I created a flowchart in GNU Radio Companion that takes a vector that is the binary representation of a single character (the character "1" as "00110001"), modulates, demodulates, and writes to a file sink.
The scope sink after demodulation looks like the values are returned (see below; appears to be correct pattern of 0s and 1s), but the file sink, although its size is 19 bytes, appears empty, or at least is not returning the correct values (I've looked at it in ASCII and Hex text editors). I assumed the single character transferred would result in 1 byte (or 8 bits) -- not 19 bytes. Changing some of the settings in the Polyphase Sync and adding a Repack Bits block after the binary slicer results in some characters in the output file, but never the right character.
My questions are:
Can GNU Radio take a single character, modulate/demodulate it, and return the same character?
Are there errors in my flowchart?
I'd appreciate any insights or suggestions, thank you.
We are using crontab to schedule jobs and it was not picking the files for processing that have [ or ] or ¿ . Is there any limitation in giving file name or these characters means something in UNIX? Is there any other variables like these we shouldnt use in file name?? Thanks in advance.
Following are general rules for both Linux, and Unix (including *BSD) like systems:
All file names are case sensitive. So filename vivek.txt Vivek.txt VIVEK.txt all are three different files.
You can use upper and lowercase letters, numbers, "." (dot), and "_" (underscore) symbols.
You can use other special characters such as blank space, but they are hard to use and it is better to avoid them.
In short, filenames may contain any character except / (root directory), which is reserved as the separator between files and directories in a pathname. You cannot use the null character.
No need to use . (dot) in a filename. Some time dot improves readability of filenames.
And you can use dot based filename extension to identify file. For example:
.sh = Shell file
.tar.gz = Compressed archive
Most modern Linux and UNIX limit filename to 255 characters (255 bytes). However, some older version of UNIX system limits filenames to 14 characters only.
A filename must be unique inside its directory. For example, inside /home/vivek directory you cannot create a demo.txt file and demo.txt directory name. However, other directory may have files with the same names. For example, you can create demo.txt directory in /tmp.
Linux / UNIX: Reserved Characters And Words
Avoid using the following characters from appearing in file names:
/
>
<
|
:
&
Please note that Linux and UNIX allows white spaces, <, >, |, \, :, (, ), &, ;, as well as wildcards such as ? and *, to be quoted or escaped using \ symbol.
It will be good if you can avoid white spaces in your filename. It will make your scripting a lot more easier.
I got the answer from this link. I am just pasting it here so that this info will be available even if that website goes down.
The only characters that are actually illegal in *nix filenames are / (reserved as the directory separator) and NUL (because it's the C string terminator). Everything else is fair game, although various utilities may fail on certain characters - typically characters that have special meaning to the shell. These will need quoting or escaping to be handled correctly.