I am writing a terminal-based application, but I want the user to be able to edit certain text data in a separate editor. For example, if the user chooses to edit the list of current usernames, the list should open as a text file in the user's favorite editor (vim, gedit, etc.). This will probably be an environment variable such as $MYAPPEDITOR. This is similar to the way commit messages work in svn.
Is the best way to do this to create a temporary file in /tmp, and read it in when the editor process is terminated? Or is there a better way to approach this problem?
There's already a $EDITOR variable, which is extremely standard and I have seen it working on a wide variety of unixes. Also, vi is always an option on any flavor of unix.
Debian has a sensible-editor command that invokes $EDITOR if it can, or falls back to some standard ones otherwise. Freedesktop.org has an xdg-open command that will detect which desktop environment is running and open the file with the associated application. As far as I know, sensible-editor doesn't exist on other distributions, and of course xdg-open will fail in a text-only environment, but it couldn't hurt to try as many options as possible, if you think it's important that a desktop user can see their happy shiny gedit or kate instead of scary old vi or nano. ;)
The way crontab and sudoedit work is also by making a file in /tmp. git puts it under .git, and svn actually puts it in the current directory (not /tmp).
The way svn and mercurial do it is by making a file in /tmp.
BTW, you don't need a MYAPPEDITOR, on nix there's EDITOR already present.
Since you mention svn in your post, why not just follow the same methodology? svn opens a file with a particular name with whatever $EDITOR (or $SVN_EDITOR) contains - this might actually require some work on your part; determining the parameters to each supported editor. In either case, you have the name of the file that was saved (or the error code of the application if something failed) and you can just use that.
Related
I want to build file sync software. Is there any way to get exact file changes (or at least changes size) with kernel systems like I-notify or others?
EDIT:
I'm interested in the following scenario with I-notify:
When getting IN_MODIFY event on a file I want retrieve in some way changed lines of the file (some kind of a file diff format). Are there any linux kernel tools to achieve this?
Even if there were such a kernel feature, it would not work in practice. You see, most editors modify files by creating a copy, then renaming it over the original one. This way the user is assured of getting either the old contents or the new contents, never a mix between the two.
The only real option is to take snapshots of the file (at e.g. when file is closed when it was open for writing, or when the file is replaced with a new one), and compare the snapshots, to find which part was changed.
Comparing two versions of a file to see which part of it was changed is itself a difficult question, as it definitely depends on the file format. For source code, unified diffs work well, but for other types (including plain text files that are not line-oriented), it's not that simple.
Could you please refine your question? The inotify API on Linux does monitor such changes, and similar changes such as if a file was open, if a file inside a directory (or the directory itself) was moved and file deletions etc.
For more, see here:
(http://man7.org/linux/man-pages/man7/inotify.7.html)
EDIT:
I believe I misread the question the first time around, if I did, yes such programs exist and the inotify API is the primary one existing within the Linux kernels. See the above link for a comprehensive guide on the different functions it provides.
Im want to build a file system for non-tecks( dont care about old versions of the file so no merging or svn/git). The thougt is that a user should be able to download a file, in the same instance the file should be locked for other users. When the first user is done editing the, the file should then automaticaly upload to the server. When he closes the file, the lock should den be opend.
Is this even possible? Im thingking a sort of browser plugin, but I cant find anywone that has done the same thing. (besides microsoft, but who want to go down that road)
That would be: Sharepoint, Alfresco, (almost every WIKI), ...
Actually that is a basic feature of most document management systems. Even SVN has that already and IIRC you can set that up with mod_dav_svn without a line of code (considering configuration is not code).
Also the interesting question is, IMHO, not TheHappyCase where the described unit of work goes well but what about this*:
I Checkout 50 random documents you need
(get some popcorn and wait for your stresslevel to go up)
?????
I get bored and forget about it (everything still being checked out)
*: Points (1) and (2) may change order
I recently released a software to our customer, it will be installed on one machine at one location and maybe later at two other locations. It is a prototype and has to be tested.
This is a compiled Matlab GUI which runs scanning, does some image analysis and produces report. All is fine here. But I've got a complaint that batch-file I use is a thing from past DOS times, should not be used and looks unprofessional... Currently, the user should set up one path in batch file before the first use and then always run batch file. This bat-file kills some processes to avoid conflicts, including any running instances of the GUI, sets the path for results and runs the GUI. I proposed them to create a shortcut to this bat-file with a nice logo (such that they don't see the .bat extension ;)), but they are still unhappy.
What to do is probably not the main question here - client is always right and I should remove .bat somehow to make them happy. But is it really so unprofessional to release technical, not mass software using bat-files? Or is it just one person's opinion?
Personally I think if you already have a GUI, then use that to do the pre-processing. There is nothing wrong with using batch files, but using one when you have a GUI doesn't seem like the best way to do it.
Alternatively create a GUI with the same look as the main program to ask the user for the details it needs. For me it's not about professionalism, but how easy it is for the user to do what they need to do.
I see nothing wrong with using a batch file for small projects (especially during the testing phase if that is easier for you and delivers something to the client quicker). However, depending on the size of the project, it is nice to have an EXE to deliver to the client with a proper icon and what not.
I would agree with the customer that an EXE looks more professional. Whether it is or not... I'm not sure. The .bat files just seem a little slapped together whether that is true or not.
I would say this is similar to when people call PHP programs scripts because a lot of the times they are simple scirpts. But, then there are frameworks out there like Cake and Kohanna that are more than what someone would typically classify as a script but, since it's PHP there is still that connotation.
A batch file is not unprofessional. The batch "language" has disadvantages and outright problems (error handling!!) but it gets the job done and that's the point.
The problem is that it shows the internals of the program and some people are scared by this. They don't want to see anything like this and so try to find a disapproving label. The quickest solution is to hide the batch file behind a "vanity cover", or in this case an exe that hides the working from terrified eyes.
One simple possibility is to use an self-extracting zip file eg: http://www.7zsfx.info/en/
I make a fair amount portable Apps for personal use and they work perfectly for the most part. I do, however, find it quite frustrating that if I run them on another computer none of my preferences are retained, as a program always looks in appData for the configuration files (which obviously don't exist on another system), so I'm wondering whether there is some kind of command line to launch an .exe with a custom .ini location.
I'm asking this firstly because Google has proved fruitless (once again) and secondly because I know it's possible - I've actually done this before, but with only one of my Apps. I accomplished this by launching the App via the command programFile.exe -f configFile.ini /s (I have also seen programFile.exe -d -f configFile.ini /s elsewhere). Naturally, I thought I would try to apply this to some other Apps but it seems it only works for that particular App.
So, is there a command/switch that I am unaware of that will do this for an .exe file?
Thanks
It really depends on each executable file you are using. Some have support for what you are looking for, and some don't. Some programs don't even use .ini files. What you should look for is if each and every program you use have support for user data custom location.
Edit
The only case where generic arguments would be avaialble for a group of EXE files is if they are generated with the same tool, which automatically provides these arguments for you. InstallShield and MSI install programs have that kind of feature (with the silent install and automated installation for instance).
I suggest you look into the tool you are using to generate your portable Apps, and see if it does provide those generic arguments for you, and how they work. If it does not have that feature, then look into the Apps you were able to specify a custom location for your INI file. Somewhere into the code, there must be a piece of code that handles the arguments you specify to the EXE file and handles them. You should share that piece of code with your other Apps, to make sure they provide the same arguments list.
[the following is a rephrase of my previous question, which was deemed ambiguous].
I'm digging into creating a basic licensing mechanism for a demo application. What I have in mind goes like that: the application creates an empty "license file" called, say "0b1xa487x.ini" upon the first run, then expires 30 days after it has been first executed and can't be run anymore as long as that specific file is present on the system.
What I'm looking for is a method to protect that specific file in a way to deter deletion. Since it will be a blank file, devoid of any content, I wouldn't mind it to be corrupt, have corrupt headers, invalid date, whatever it takes to stay undeletable.
I've seen a similar approach somewhere based on file attributes (the file had the HX attributes set in place); however, the attribute approach lead me nowhere, as I can't find any documented feature on the existence of a file attribute X.
I also know that there are other approaches including rootkit drivers and system services launched as system user, but this particular one seems to fit best in this scenario. Again, I outline that the file's contents may as well be inaccessible, I'm not planning to use the approach in running any kind of malware from the file, as I've been accused below :)
Corrupt suggests not conforming to some standard. There are no standards for blank files.
Thanks everybody for your suggestions. I found a way to render my file inaccessible, namely by using fortunate combination of file permissions. The downside is that these things don't work on non-NTFS partitions. The good thing is that I can always clean up after my application by simply removing these permissions programatically and deleting everything afterwards.
Regarding your last answer to Henk, I believe it is more easier to create a service, start it automatically with the OS, and open the file in the fmShareExclusive by using a TFileStream.
But, you can not force the kernel of the OS, or an antivirus to make your file 'undeletable'.
Best regards,
Radu