use Image::Imlib2;
my $a = Image::Imlib2->load("/foo/file");
gives me the following error:
Runtime error: Image::Imlib2 load error: File does not exist at (eval 469) line 6.
Note that /foo/file is a CIFS mounted directory and this only happens for files on CIFS mounted directories. An additional complication is that this happens on Debian Squeeze but not on Debian Lenny.
The solution is to mount the CIFS directory using the 'noserverino' option.
Image::Imlib2 is a Perl wrapper around the Imlib2 C library. The problem is CIFS servers can return inode integer values > 31^2. This makes programs not compiled with LFS (Large File Support), to throw a glibc EOVERFLOW error. Either compile the program with LFS support (i.e. with -D_FILE_OFFSET_BITS=64) or use the "noserverino" mount option. But you may not be able to detect hardlinks properly.
http://linux.die.net/man/8/mount.cifs
Related
I am using Windows Powershell (on windows 10). I am also using the latest version 2.3.0.5 of docker desktop. When I type "docker version" in powershell the command is not recognized. The error message reads "Der angegebenen Datei ist keine Anwendung zugeordnet." (English: No application is assigned to the specified file). When I instead include the file extension and type "docker.exe version" the command can be executed. The interesting thing is that "docker version" works in a cmd window, but for some reason not in powershell. The extension ".exe" is contained in the windows environment variable PATHEXT.
What could be the reason that it doesn't work in powershell?
PS: I had an old version of docker installed before. There everything worked fine. Then I updated to the newest version. After that I couldn't use my existing docker containers anymore. So I uninstalled the old version and installed version 2.3.0.5. Since then I have this issue.
tl;dr:
Run Get-Command -All docker | ForEach-Object Path
Among the file paths returned, remove those that do not end in *.exe (use Remove-Item).
The likeliest explanation is that, in one of the directories in your system's path ($env:PATH) that comes before the one in which docker.exe is located, contains another file whose base name is docker:
Either: It is an extension-less file literally and fully named docker [This is what it the problem turned out to be] .
PowerShell unexpectedly tries to execute this extension-less file, because it considers it executable, despite - by definition - not having an extension designated as executable via the PATHEXT environment variable ($env:PATHEXT).[1]
This would explain cmd.exe's different behavior, because it sensibly never considers an extension-less file executable.
Presumably, the uninstallation of the old Docker version removed the original docker.exe, but left an extension-less docker file in the same directory behind (possibly a Unix shell script).
Or: It does have an extension (other than *.exe), which:
refers to a file that isn't directly executable and needs an interpreter - a separate executable - in order to be executed
and that extension is listed in the PATHEXT environment variable
and the association between the filename extension (e.g., .py) and the (information about the) associated interpreter is (now) missing, possibly as a result of having uninstalled the older Docker version.
[1] In fact, PowerShell unexpectedly considers any filename extension executable - see GitHub issue #12632.
However, for those extensions not listed in PATHEXT, execution via the path only works if you include the filename extension in a file-name-only call (e.g., executing file.txt opens a file by that name located in the first folder in the path that has such a file in the associated editor). With an extension-less file, there is obviously no extension to include, which is why confusion with an *.exe file of the same base name is possible (unless you invoke with .exe); if both such files reside in the same directory in the path, the *.exe file takes precedence, but if the extension-less file is in a different directory listed earlier in the path, it takes precedence.
I've setup some Nearline buckets and enabled versioning and object lifecycle management. The use-case is to replace my current backup solution, Crashplan.
Using gsutil I can see the different versions of a file using a command like gsutil ls -al gs://backup/test.txt.
First, is there any way of finding files that don't have a live version (e.g. deleted) but still have a version attached?
Second, is there any easier way of managing versions? For instance if I delete a file from my PC, it will no longer have a live version in my bucket but will still have the older versions associated. Say, if I didn't know the file name would I just have to do a recursive ls on the entire bucket and sift through the output?
Would love a UI that supported versioning.
Thanks.
To check if the object currently has no life version use x-goog-if-generation-match header equal to 0, for example :
gsutil -h x-goog-if-generation-match:0 cp file.txt gs://bucket/file.txt
will fail (PreconditionException: 412 Precondition Failed) if file has a live version and will succeed if it has only archived versions.
In order to automatically synchronize your local folder and folder in the bucket (or the other way around) use gcloud rsync:
gcloud rsync -r -d ./test gs://bucket/test/
notice the trailing / in gs://bucket/test/, without it you will receive
CommandException: arg (gs://graham-dest/test) does not name a directory, bucket, or bucket subdir.
-r synchronize all the directories in ./test recursively to gs://bucket/test/`
-d will delete all files from gs://bucket/test/that are not found in./test`
Regarding UI, there already exists a future request. I don't know anything about third party applications however.
I have a perl project packaged by Par::Packer and distribute by RPM on RedHat.
I found that a par-hex{6} directory would be created after each user run my command.
$ /tmp
lirian 19M par-6c3973
andy 19M par-6d6a7a
raymond 19M par-726679
john 19M par-736a69
Can I reduce the par directory size or use one shared par folder among all user?
More: I've read the instruction on pp and PAR::FAQ#RPM.
I use pp -d to package the par file.
I think I found an not-so-perfect but enough answer.
Now I use "pp -d -T lirian-tool" to package my perl script.
According to pp-option-page:
-T, --tempcache
Set the program unique part of the cache directory name that is used if the program is run without -C. If not set, a hash of the executable is used.
When the program is run, its contents are extracted to a temporary directory. On Unix systems, this is commonly /tmp/par-USER/cache-XXXXXXX. USER is replaced by the name of the user running the program, but "spelled" in hex. XXXXXXX is either a hash of the executable or the value passed to the -T or --tempcache switch.
So now we have /tmp/par-User/cache-lirian-tool. Each user's cache directory may take 20M, which is acceptable.
And you can cleanup the cache by running "pp -c":
-C, --clean
Clean up temporary files extracted from the application at runtime. By default, these files are cached in the temporary directory; this allows the program to start up faster next time.
I want to copy a particular file using Makefile and then make this file executable. How can this be done?
The file I want to copy is a .pl file.
For copying I am using the general cp -rp command. This is done successfully. But now I want to make this file executable using Makefile
Its a bad practice to use cp and chmod, instead use install command.
all:
install -m 0777 hello ../hello
You can use -m option with install to set the permission mode, and even note that by using the install you will preserve not only the permission but also the owner of the file.
You can still use chmod accordingly but it would be a bad practice
all:
cp hello ../hello
chmod +x ../hello
Update: install vs cp
cp would simply copy files with current permissions, install not only copies, but also can change perms/ownership as arg flags. (This is what your requirement was)
One significant difference is that cp truncates the destination file and starts copying data from the source into the destination file. install, on the other hand, removes the destination file first.
This is significant because if the destination file is already in use, bad things could happen to whomever is using that file in case you cp a new file on top of it. e.g. overwriting an executable that is running might fail. Truncating a data file that an existing process is busy reading/writing to could cause pretty weird behavior. If you just remove the destination file first, as install does, things continue much like normal - the removed file isn't actually removed until all processes close that file.[source]
For more details check these,
install vs. cp; and mmap
How is install -c different from cp
What module would you recommend to get a disk name on Linux? I've done some search on CPAN but all modules I've found are too old. In Bash I can use something like:
disk_name=$(df |grep -w '/'|awk '{print $1}'|cut -d/ -f3)
echo $disk_name
sda6
Please help me to understand how to do same in Perl.
Thanks.
The "proper" way to list mounted disks on Linux is through the getmntent() system call, which can be accessed from Perl using the Quota module:
use Quota;
Quota::setmntent();
while (my ($dev, $path, $type, $opts) = Quota::getmntent()) {
print "The root device is $dev.\n" if $path eq "/";
}
Quota::endmntent();
As a bonus, using the Quota module to list device mount points should be fairly portable to other Unixish systems, which parsing various system files or the output of df may not be. Unfortunately, this seemingly basic module is not included in the standard Perl distribution, so you have to get it from CPAN (or from your distro's package repository — for example, Debian / Ubuntu have the libquota-perl package).
Ps. Simply splitting the device name on / and taking the third element (as your cut command does) is not a safe way to turn, say, /dev/sdb1 into sdb1. Some issues with it are that:
Not all block devices have to live under /dev — it's really just a convention.
Even if the device file is under /dev, it might be in a subdirectory of it. For example, my root filesystem is on the device /dev/disk/by-uuid/627f8512-f037-4c6c-9892-6130090c0e0f.
Sometimes, the device name might not even be an actual filesystem path: for example, virtual or in-memory filesystems such as tmpfs are often mounted with the device name none, but it's possible to use any device name with them.
If you do want to get rid of the /dev/ part, I'd suggest a conservative approach using a regexp, for example like this:
if ($dev =~ m(^/dev/(.*)$)s) {
print "The directory $path is mounted from device $1 under /dev.\n";
} else {
print "The directory $path is not mounted from a device under /dev.\n"
}
What you're describing is not the disk name but the device name of the block device representing the partition mounted at root (/). On a regular computer it would normally be something like /dev/sdXN or /dev/hdXN with X being the disk number (primary hard drive is usually A, secondary is B, etc.) and N is the partition number on that device.
Provided you're always running on a unix system, you can try reading /etc/mtab file, which lists all mounted partitions, or the special file /proc/mounts, which pretty much does the same. You'll need to parse it afterwards to find the one you need and get the device name from it.
Alternatively, you can just run df as a process and get its input into perl, something like
open(DF, "df|");
#mount_points = <DF>;
close(DF);
and then iterate over the data to find what you need. I'm not aware of any modules of the top of my head that would do the job for you, but the code seems pretty simple to me anyway.
P.S. Note that Max OS X, while being a derivative of BSD, doesn't have the same file structure and therefore this approach wouldn't work. On Mac OS X, you can read file /etc/fstab.hd, which contains similar info but in a slightly different format.
One way to do just what you are doing in the question
df / | perl -ne 'm"^/\w+/(\w+)";print "$1\n" if defined $1;'
but using a CPAN library to do it is probably better.