the dpkg / var / lib / dpkg database directory cannot be accessed: no such file or directory exists

sudo dpkg --configure -a

gave this error below
dpkg: error: database directory cannot be accessed dpkg / var / lib / dpkg: There is no such file or directory
sudo rm /var/lib/dpkg
ps aux | grep -i apt
also lsof /var/lib/dpkg/lock-frontend as well…

apt – Could not get lock / var / lib / dpkg / lock-frontend – specific for a single .deb package

I have a custom package that I am trying to install on my device.

Returns this error:

nvidia@tegra-ubuntu:~$ sudo dpkg -i MyPackage.deb 
(Reading database ... 181574 files and directories currently installed.)
Preparing to unpack .../MyPackage.deb ...
E: Could not get lock /var/lib/dpkg/lock-frontend - open (11: Resource temporarily unavailable)
E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), is another process using it?
dpkg: error processing archive MyPackage.deb (--install):
 subprocess new pre-installation script returned error exit status 100

I already tried all the traditional ways to remove a lock:

None of those worked for me. I can't find any running process related to to block or lock interface records. I also noticed that this problem is related to this specific package. Any other version of this same package or any other package is installed correctly and does not cause a tany error.

Any ideas ?

After the restoration, the mysql databases are not in / var / lib / mysql but can query

I have restored a mysqldump database and the restored database and the data is there. Unfortunately, the database files are missing in / var / lib / mysql. /Etc/my.conf shows that this is the directory. This is causing problems because remote queries get a database not found. Is there any way to fix this problem? I tried to create a new database and restore the previous database, but again the files do not appear in / var / lib / mysql.

linux – restore the contents of the lib folder in var

being new in ubuntu, I I accidentally deleted my lib folder contained in var (var / lib *). Now, impossible to install a package, I tried to make a "sudo apt-get reinstall kubuntu-desktop"Y"sudo apt-get build-dep kubuntu-desktop"to restart the system and all the dependencies, but I get an error like this:

sudo apt-get build-dep kubuntu-desktop

E: The lock file could not be opened / var / lib / dpkg / lock-frontend – open (2: there is no such file or directory)
E: You can not acquire the dpkg frontend lock (/ var / lib / dpkg / lock-frontend), are you rooted?

How can I solve this problem ?

linux – lapack-3.8.0 linkage error lib: / usr / bin / ld: I can not find -lrefblas

I am trying to compile my code and return this error information:

usr / bin / ld: can not be found – lrefblas
collect2: error: ld returned 1 output
state makefile: 11: the recipe for the goal & # 39; a.out & # 39; failure
do: *** [a.out] Error 1

In the makefile, I use the gfortran command and the link to the static library located in another directory. My order is the following:

gfortran $ (GOBJ) -mcmodel = medium -O3 -fopenmp -o a.out -L / home / Desktop / lapack-3.8.0 -llapack -lrefblas

My development environment is:
Dealer ID: Ubuntu
Description: Ubuntu 18.04.1 LTS
Release: 18.04
Code name: bionic


Is there any suggestion to make it work?

Where can I find more detailed documentation about lib secp256k1?

Basically I am reading the comments of the header file and some of the code.

In particular, I am interested in more explanations about the modification options for addition and multiplication, and their applications to private and public keys.

I'm going to choose an example of secp256k1.c file in the source:

int secp256k1_ec_privkey_tweak_add (const secp256k1_context * ctx, unsigned char * seckey, const unsigned char * tweak) {
secp256k1_scalar term;
secp256k1_scalar sec;
int ret = 0;
overflow int = 0;
ARG_CHECK (seckey! = NULL);
ARG_CHECK (tweak! = NULL);

secp256k1_scalar_set_b32 (& term, tweak, & overflow);
secp256k1_scalar_set_b32 (& sec, seckey, NULL);

ret =! overflow && secp256k1_eckey_privkey_tweak_add (& sec, & term);
memset (seckey, 0, 32);
yes (ret) {
secp256k1_scalar_get_b32 (seckey, & sec);

secp256k1_scalar_clear (& sec);
secp256k1_scalar_clear (& term);
back ret


And the functions secp256k1_scalar_set_b32 () Y secp256k1_scalar_get_b32 () It seems to be related to the partition of the 32 bytes of the scalar in 4×64 bits or 8×32 bits (or something else) to perform group operations. Just looking at the code is not very clear to me.

In the comments to secp256k1_context_randomize () it is said, the quote "the code secp256k1 is written to be of constant time no matter what secret". So, broadly speaking, are the adjustments a way to avoid the general construction that makes the whole implementation constant (due to the prevention of lateral channel leakage)?

I would appreciate pointing out references in the literature as well.

magento2 – The LESS Grunt compile fails with an error when compiling lib / web / css / docs / source / docs.less

I hope to get some advice. I took out a project that I had not touched in a long time and in developer mode I ran & # 39; grunt exec & # 39; followed by & # 39; grunt less & # 39; and once running & # 39; grunt less & # 39; I received the following error. Magento 2.2.6

Running the "less: documents" (less) task

NameError: .lib-url-check is not defined in lib / web / css / docs / source / _utilities.less in line 402, column 5:
401 // "Call" the mixin
402 .lib-url-check (@_ icon-image);
403 Warning: Error compiling lib / web / css / docs / source / docs.less Use –force to continue.

Aborted by warnings.

The code for around line 401:

.example-url-check-false {
// Set the path to use the image in false
@ _icon-image: false;

// "Call" the mixin
.lib-url-check (@_ icon-image);

// will return & # 39; false & # 39; and it does not generate anything
.lib-css (background, #eee @ lib-url-check-output non-repetition 0 0);

This file is an unmodified central file, how do I debug the cause of this problem / resolution?

I would appreciate any help you may receive.

Thank you!