I have a program that I need to run under *nix and windows. because the program takes file paths from files the issue is what to do about the \ vs / issue.
My current thought is to put in a regex that converts the wrong one to the right one depending on what system I'm on. This will have the effect of letting either type work on either system. Aside from the fact that now I have two problems, does anyone see any other problems?
(Other better solutions are more than welcome)
Edit: the primary issue is getting windows paths to work on unix rather than the other way around.
The / is fully supported in win32 too.
Also see this related question
Windows will generally accept either \ or /,so standardizing on / may make your problem simpler as long as you have complete control over the filenames.
Have you considered creating a "file manager" class that will handle all of the file pathing issues for you? That way in your mail application, when you're loading a data file, you can call something like this.
LoadApplicationData(FileManager.GetDataFilePath)
Then your file manager will detect the environment that it is in and return the proper file path option. That way you can also accomodate for Win32 vs. Unix locatio standards (like Program Files vs /usr or whatever) as well.
Note that Win32 paths are complex when you consider drive letters (no analog on Unix) and the special 'forks' (MacOS pre-X term - likewise no analog on Unix in general, though MacOS X has them - surprise, surprise) that can be provided. Be careful.
Create a parser for your input to create a tree structure of nodes representing directories. Then you can 'save' by walking the tree and writing whatever delimiters you want or optionally doing different things, like checking if the directory exists or writing meta files. This is actually something that I am just now thinking would be useful for my own application :-)
You didn't say what language you are using, so I'm going to selfishly assume c/c++. boost, if you are willing to use it, has a filesystem library. Of course, if you are using a dynamic language, FS abstraction libraries probably already exist there too (e.g. in perl, File::Spec is quite standard).
You haven't told us what sort of files you are reading paths in from. I am going to assume that they are config files. In which case, there are many ways, IMHO the correct answer is to design your program to avoid manipulating paths, if possible. I posted an answer here: https://stackoverflow.com/a/40980510/2345997 which is relevant.
ways:
Add a command line option which allows a user to specify the path in question instead of reading it from a config file.
Add a command line option so that the user can specify a base path. Paths in the config file will be interpreted as located under this base path.
Split your config file into three. One file will have cross platform configuration, another file will have windows only configuration and a final file will have Linux only configuration. Then the user can specify the correct path for both Windows and Linux. On windows your program will read the cross-platform config file and the windows only config file. On Linux it will read the cross-platform file and the Linux only config file.
Add preprocessing to your config file parsing. This will allow you to have one config file where the user can make your program ignore some of the lines in the file depending on which OS the program is running on. Therefore, the user will be able to specify the path to the file twice. Once for Linux, and once for Windows.
Change the design so that the files are always located in the same directory as your executable - then the user only specifies file names in the config file rather than paths to files.
Use a simple function that switches "/" to "\". Then document to the user that they must specify paths as Linux paths and this transformation will be applied for windows.
Create your own path mini-language for this and document it to the user. E.g: "/" - specifies a directory separator, {root} - expands to the root of the filesystem, {cwd} - expands to the current directory, {app} - expands to the path to your application etc... Then the user can specify file paths like: {root}/myfiles/bob.txt on both platforms.
Some paths will work on both platforms. E.g: relative paths like ../my files/bill.txt. Restrict your application to only work with these paths. Document this limitation and how your application handles paths to the user.
Related
I'm new to octave, and want to run a few commands on startup automatically every time it opens.
I typed "help startup" and saw "Octave uses the file ".octaverc". I did a bit of searching online at https://www.math.utah.edu/docs/info/octave_4.html, and saw the .octaverc file should be in the following path:
OCTAVE_HOME/lib/octave/VERSION/startup/octaverc
PROBLEM:
In that directory I don't have a startup folder, only "oct" and "site". I do see hidden files, which was my first thought since the file begins with "." character. So I then used Agent Ransack in the directory, and still nothing came up.
QUESTION:
1) Do I have to make the startup folder and octaverc file myself?
2) If so, does one, both or none have to be hidden?
3) Can it be a txt file, or does it have a special extension?
4) Do I just type the commands straight into the file or is there special formatting?
NOTE:
In case I'm going about this the wrong way, there are the operations I'd like to have run on startup:
PS1('>> '), addpath('D:\Users\Me\Desktop'), clc
Thanks ahead of time for the help!!
Possible locations (and their differences) for octaverc files are specified in the documentation.
In short, these are, from more general to specific:
octave-home/share/octave/site/m/startup/octaverc (most generic, for entire system)
octave-home/share/octave/version/m/startup/octaverc (to cover for more than one octave versions installed on the system, possibly requiring different startup scripts)
~/.octaverc (where ~ is unix-speak for a user's home directory -- covering for user-specific startup files)
.octaverc files in any directory, creating specific startup conditions for specific directories
octaverc files are effectively simple script files that are executed from most generic to most specific each time octave starts. Therefore, in the presence of conflicting commands, the more specific file can effectively be used to override the more generic behaviour.
Octave also supports (but does not recommend) the use of the startup.m file, for matlab compatibility.
You might also want to check out pathdef and savepath as well.
As a more general tip, if you ever want to search for a specific keyword from the documentation (e.g. octaverc), you can type this kind of search query in duckduckgo (or google):
octaverc site:https://octave.org/doc/interpreter/
(or just download the documentation as pdf and search the pdf)
Found the solution, the file was in the following path:
OCTAVE_HOME/share/octave/site/m/startup
to find out where OCTAVE_HOME is for you, just type "OCTAVE_HOME" into your Octave command line window.
ANSWERS:
1) You do not have to make a startup octaverc file yourself
2) The file is actually not hidden, so it should be easy to find given you're looking in the right place.
3) The file doesn't have an extension. It's just octaverc.
4) Under the last line of the existing file, you can just append commands as you would type them at the Octave command line window.
the last(7.3.0) octave version placed HERE:/ does not find the THERE:/openEMS/matlab directory even it is already loaded with octaverc or addpath. It keeps looking into the work dir where openEMS is not placed and does not recognize, for instance, the 'physical_constants.m' file.
Is it possible to append/remove a ressource file to a binary at execution time?
I have an application written with go, which saves/searches data from a database file, and i would like this database file to be embedded to the binary, and updated by the application itself.
This way the application would be self contained with its database.
Modifying the executable, this is generally a very bad idea.
Several issues pop right into my head, such as:
Does the current user have sufficient permissions?
Is the file locked during execution?
What about multiple running instances of the application?
Even if you manage to do just that, think of what anti-virus and firewall applications will say to it: most when they detect the change will flag the executable and/or contain it, or deny running it, or some may even delete it. Rightfully, as this is what many viruses do: modify existing executables.
Also virus scanner databases maintain reports where files (their contents) are identified based on the hash of their content. Modifying the executable will naturally change the file content hash, thus render the file unknown / suspicious to these databases.
As mentioned, just write / cache data in separate file(s), preferably in user's home folder or in the application folder (next to the executable, optionally in sub-folders). Or make the cache file / folder a changeable option (command line flags).
Technically, this is possible, but this is a bad idea. Your application could be run by users not having write permissions to your binary.
If you're talking about a portable app, your best option might be using a file in the same directory the binary is located, otherwise - use the user's home directory according to the conventions of the OS you're running on. You can use the os/user package to find the home directory.
Where does an application look when a file is searched for? Where is it created? It's rarely realistic to always specify the absolute path. E.g. I tried saving text files that were going to be used in a Visual Studio 2010 app in the local bin of the project solution, but always got a run-time error.
It's usually the folder it was called from. You can find it using _getcwd: http://msdn.microsoft.com/en-us/library/sf98bd4y%28VS.80%29.aspx
If you use a relative path, the path you supply is combined with the working directory of the process.
It's very hard to maintain control over the working directory of a GUI process. That's because GUI processes tend to be started in lots of different ways. What's more, file dialogs have a tendency to change working directory. Finally, the working directory is shared between all threads in the process, and can be changed by any thread. There are lots of pitfalls.
So in a GUI process I suggest that you never use relative paths. Or, if you do use relative paths, you convert them to absolute paths before using them. And perform that conversion against a well-defined root path.
Unless you are writing a portable app, you should not expect to be able to save to the directory which contains the executable file. On modern systems executable files are often located in read-only directories.
If you want to save user settings, save them at an appropriate location in the user's profile.
On the other hand, if you are wanting to read files, that you never modify, then it's reasonable to store them alongside the executable. But even in that case, open the file using a full absolute path. Create that path by combining the directory which contains the executable, with the relative path to the file.
So, to summarise, you said:
It's rarely realistic to always specify the absolute path.
But I disagree. I would counter that using an absolute path is very often the best option. But you don't have to hard code the absolute path. You can, and should, create it at runtime.
My application is to be written using wxWidgets, but the question may be related to using gettext in general.
For the application named app, some sources suggest I sould create <lang>/ subdirectory, create the app.po file inside with the translation, and convert it to the distributed app.mo file in the subdir.
Another approach is to create app.pot (i.e. the template from the sources via xgettext), and to msginit and msgmerge it to the <lang>.po for the language.
For the first approach, more .mo files can be put inside the <lang>/ subdirectory. Also the wxLocale::AddCatalog() gets the domain name (where the domain can naturally be app, wxstd, etc.). On the other hand, the <lang>.po file name is descriptive on itself -- wherever it is located.
What are the pros and cons of the two approaches? Is there any text that explains the path to be chosen?
Thanks for your time and experience,
Petr
The Unix convention is to use app.mo for binary catalogs, see the contents of /usr/share/locale directory. Sometimes lang.po is however used for the source ones, as done in wxWidgets itself (see its locale subdirectory), but they're still installed into language-specific subdirectory using the app-dependent name.
I've developed a GUI for some build scripts, and am now in the process of deploying it. As the script will be deployed to a number of different machines at various points, I need to use the standard format of directories that the team use.
The GUI consists of a ".fig" file that contains the visual definition of the UI, and a m-script that defines the functionality. I need to locate these two in "fig/" and "m/" folders respectively, but I can't figure out how to. I first searched for an include statement of some kind in the m-script, as when I Run it on its own, the error message in the command window states that the ".fig" file can't be found, but there doesn't seem to be a reference to the ".fig" file anywhere, I assume that it's inferred as both files have the same name but a different extension.
I fear that Matlab's GUI system requires that both ".m" and ".fig" files are in the same location, but this will be an inelegant solution that I'd rather not go for if I can avoid it.
The next thing I'm going to try is to call a script that copies the fig file from the other directory to the same location as the m-script, when it is executed, then deletes that copy once the script exits, which again seems a clunky solution, but will allow me to adhere to the team's organisation conventions.
Does anyone else know of an undocumented means of specifying the relative location of a GUI ".fig" file?
You can export the GUIDE-generated GUI as a single .m file. Check out this blog post: GUIDE GUIs in All One File.
I'm not sure if this is a new feature, or one of those things that has always been there...