I want to check all availalble space in directory A using 'stat'. Then I want to check the size of directory B using 'du' and if directory A has enough free space, then i want to copy B into A.
The question is what arguments I need to pass to the 'stat' and 'du' commands so that they will return their output in the same format (nodes, bytes, etc...)
On Linux there is no limit to the files contained in a directory, there isn't even a limit on how many files can be placed in a directory. This can all be found in the linux manpages.
Iff the device that A is on is different from the one B is on, you may be curious about how much available space there is left on A's device. For that you use:
stat --file-system A B
Related
I'm looking for a way to automate archiving where after I plug my two external drives I can copy all my resources. The problem is that I have different file structures on my laptop and on both external drives so I need to select specific folders to be copied. It means that I can't select one root folder and copy it straightforward. I tried to find a way to declare more than one path in the cp command and in the copy command, without success. An example path:
/my_programming_stuff
/folder1
/folder2
/folder3
/folder4
I want to select only the first 3 folders to copy them into external drive1 and external drive 2. The idea is to create a .bat file that will copy everything at once ( in the best case scenario it will be copied simultaneously on both external drives, so it will be much faster). Another problem is that there needs to be a bypass the ntfs long path limitations (max. 260 characters).
Flags that I want to use:
Copy the files and directories and all of their attributes,
including ownerships and permissions.
Recursively copy directories and their contents.
When copying files from one directory to another, only
copy files that either doesn't exist or are newer than the
existing corresponding files, in the destination
directory.
data verification (so it's certain that the copy was verified)
progression bar with time eta
Until now I was using Total Commander to do this but every day I need to pick only a few folders to be copied which takes time and is inefficient.
I have experience with Bash and PowerShell but I am not sure how to handle this topic.
Create a static batch file with robocopy commands. I think /copyall is the only switch you need to specify for all this. Other defaults should satisfy requirements.
https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/robocopy
I think your time will be better spent learning how to use either FastCopy or FreeFileSynce. I used FreeFileSync some years ago but got disgusted with the it's constantly changing format of its xml file used for starting a backup, so I switched to FastCopy. But it looks like FreeFileSync may be getting their act together and I aim to do some experiments over the summer to see if I want to switch back to it.
Both can handle the long filename format issues, both can be executed by a batch file, both seem to have a lot of quality, but FreeFileSync has more features - and more bloated because of the features. But speed wise, I think FastCopy is probably one of the better products out there and very streamline in use and design.
I have about 1500 image files in a folder and listing all using dir() last too long and sometimes crashes the AppDesigner. Is there a way to list only the first or the first n images at a given time?
No, this is not possible, because dir essentially is a wrapper of a operation system function (such as the Windows dir and the Linux 'ls'). So now you have two (actually three but you're not gonna like at least one of them^^) options
it shouldn't cause much trouble to call 1500 files. Have a look if it is really the dir command, which causes trouble. Use the Rund and Time functionality in the Editor
use dir with a pattern. Eg. lst = dir() returns an array of structs with everything in the current folder -- including . and .., which are usually nothing you need. Use lst = dir('*.m') instead to get all .m files. In your case, it can be lst = dir('d_Seite_*.jpg'). I am not sure if that saves you much time but at least memory
restructure how your data (images) is stored so that there are less files available. You could run a background task that moves only the n latest files into the folder latest_files and moves them out again if there are newer ones...
I need to run an executable in background on a server, however, it takes some parameter that I do not want to expose to others. I wonder if there is any way that I can wrap this executable in another app, or preferably just by using MATLAB, that the actual executable will not be shown in top command?
I need to hide three things, 1) the parameter of, 2) the path to, 3) the CPU usage of the executable. For the CPU usage, I do not intend to trick the system to show a constant 0% percent, but I want to let the usage been shown in the wrapper app.
For example, I have an executable in /secret_path/A, which takes parameter -password 123, and consumes a constant 10% CPU usage, all these information will be very easy to be spotted if I type top in another terminal window. I want to create another executable, for example in ~/B, which hard code path and parameters of A, so I can just run B with no parameter to execute A, and instead showing a A record in top, it would be no trace of A and B will show 10% CPU usage in top.
Please suggest any way of doing that, without requiring root privilege, or why it is not possible.
You can run it in a virtual machine. That way not only the path can be hidden but the executable itself won't have to exist on the file system. If you run top you will see the VM using the CPU, which shouldn't be a problem for you since apparently you only want to hide the path of the program.
I am trying to copy files from a directory that is in constant use by a security cam program. To archive these .jpg files to another HD, I first need to copy them. The problem is, the directory is being filled as the copying proceeds at the rate of about 10 .jpgs per second. I have the option of stopping the program, do the copy then start it again which is not what I want to do for many reasons. Or I could do the find/mtime approach. I have tried the following:
find /var/cache/zm/events/* -mmin +5 -exec cp -r {} /media/events_cache/ \;
Which under normal circumstances would work. But it seems the directories are also changing their timestamps and branch off in different directions so it never comes out logically and for some reason each directory is very deep like /var/cache/zm/events/../../../../../../../001.jpg x 3000. All I want to do is copy the files and directories via cron with a simple command line if possible. With the directories constantly changing, is there are way to make this copy without stopping the program?
Any insight would be appreciated.
rsync should be a better option in this case but you will need to try it out. Try setting it up at off peak hours when the traffic is not that high.
Another option would be setting up the directory on a volume which uses say mirroring or RAID 5 ; this way you do not have to worry about losing data (if that indeed is your concern).
I am trying to find a way of monitoring directories in Perl, in particular the size of a directory, and upon detecting a change in directory size, perform a particular action.
The issue I have is with large files that require a noticeable amount of time to copy into this directory, i.e. > 100MB. What happens (in Windows, not Unix) is the system reserves enough disk space for the entire file, even though the file is still copying in progress. This causes problems for me, because my script will try to perform an action on this file that has not finished copying over. I can easily detect directory size changes in Unix via 'du', but 'du' in Windows does not behave the same way.
Are there any accurate methods of detecting directory size changes in Perl?
Edit: Some points to clarify:
- My Perl script is only monitoring a particular directory, and upon detecting a new file or a new directory, perform an action on this new file or directory. It is not copying any files; users on the network will be copying files into the directory I am monitoring.
- The problem occurs when a new file or directory appears (copied, not moved) that is significantly large (> 100MB, but usually a couple GB) and my program fires before this copy completes
- In Unix I can easily 'du' to see that the file/directory in question is growing in size, and take the appropriate action
- In Windows the size is static, so I cannot detect this change
- opendir/readdir/closedir is not feasible, as some of the directories that appear may contain thousands of files, and I want to avoid the overhead of
Ideally I would like my program to be triggered on change, but I am not sure how to do this. As of right now it busy waits until it detects a change. The change in file/directory size is not in my control.
You seem to be working around the underlying issue rather than addressing it -- your program is not properly sending a notification when it is finished copying a file. Why not do that instead of using OS-specific mechanisms to try to indirectly determine when the operation is complete?
You can use Linux::Inotify2 or Win32::ChangeNotify to detect directory/file changes.
EDIT: File::ChangeNotify seems a better option (cross-platform & used by Catalyst)
As I understand it, you are polling a directory with thousands of files. When you see a new file, there is an action that is taken on the file. This causes problems if the file is in use or still being copied, correct?
There are potentially several solutions:
1) Use flock to detect if the file is still in use by another process (test if it works properly on your OS, file system, and Perl version).
2) Use a LockFile call on Windows. If it fails, the OS or another process is using that file.
3) Change the poll interval to a non busy time on the server and take the directory off line while your process completes.
Evaluating the size of a directory is something all but the most inexperienced Perl programmers should be able to do. You can write your own portable version of du in 15 lines of code if you know about:
Either glob or opendir / readdir / closedir to iterate through the files in a directory
The filetest operators (-f file, -d file, etc.) to distinguish between regular files and directory names
The stat function or file size operator -s file to obtain the size of a file
There is a nice module called File::Monitor, it will detect new files, deleted files, changes in size and any other attribute that can be done with stat. It will then go and out put the files for you.
http://metacpan.org/pod/File::Monitor
You set up a baseline scan, then set up a call back for each item you are looking for, so new changes you can see via
$monitor->watch( {
name => 'somedir',
recurse => 1,
callback => {
files_created => sub {
my ($name, $event, $change) = #_;
# Do stuff
}
}
} );
If you need to go deeper than one level just do it to whatever level you need. After this is done and it finds new files you can trigger you application to do what you want on the files.