**Copy the public key to clipboard.**

Linux

    ssh-keygen -f private.pem -y | xclip

MacOS

    ssh-keygen -f private.pem -y | pbcopy

**Save to file**

    ssh-keygen -f private.pem -y &gt; public.pub


Note that if your permissions are vague on the `.pem` file, then `ssh-keygen` will generate an empty `.pub` file.

You can usually fix this with:

    chmod 400 private.pem 

JazzCat&#39;s answer works. small addition: if your permissions are vague on .pem file, ssh-keygen will generate empty .pub file. 

if you see any complains on terminal about private key too open, try to narrow it using `chmod 400 private.pem` and retry above command.

ps: sorry I don&#39;t have permissions to add a comment instead of answer.

I am newbie in convolutional neural networks and just have idea about feature maps and how convolution is done on images to extract features. I would be glad to know some details on applying batch normalisation in CNN.

I read this paper https://arxiv.org/pdf/1502.03167v3.pdf and could understand the BN algorithm applied on a data but in the end they mentioned that a slight modification is required when applied to CNN:

&gt; For convolutional layers, we additionally want the normalization to obey the convolutional property – so that different elements of the same feature map, at different locations, are normalized in the same way. To achieve this, we jointly normalize all the activations in a mini- batch, over all locations. In Alg. 1, we let B be the set of all values in a feature map across both the elements of a mini-batch and spatial locations – so for a mini-batch of size m and feature maps of size p &#215; q, we use the effec- tive mini-batch of size m′ = |B| = m &#183; pq. We learn a pair of parameters γ(k) and β(k) per feature map, rather than per activation. Alg. 2 is modified similarly, so that during inference the BN transform applies the same linear transformation to each activation in a given feature map.


I am total confused when they say
**&quot;so that different elements of the same feature map, at different locations, are normalized in the same way&quot;**

I know what feature maps mean and different elements are the weights in every feature map. But I could not understand what location or spatial location means.

 I could not understand the below sentence at all
**&quot;In Alg. 1, we let B be the set of all values in a feature map across both the elements of a mini-batch and spatial locations&quot;**

I would be glad if someone cold elaborate and explain me in much simpler terms 

Batch Normalization in Convolutional Neural Network

When I run `!pip install geocoder` in Jupyter Notebook I get the same output as running `pip install geocoder` in the terminal but the geocoder package is not available when I try to import it.

I&#39;m using Ubuntu 14.04, Anaconda 4.0.0 and pip 8.1.2

**Installing geocoder:**

    !pip install geocoder

    The directory &#39;/home/ubuntu/.cache/pip/http&#39; or its parent directory is not owned by the current user and the cache has been disabled. Please check the permissions and owner of that directory. If executing pip with sudo, you may want sudo&#39;s -H flag.
    The directory &#39;/home/ubuntu/.cache/pip&#39; or its parent directory is not owned by the current user and caching wheels has been disabled. check the permissions and owner of that directory. If executing pip with sudo, you may want sudo&#39;s -H flag.
    Collecting geocoder
      Downloading geocoder-1.15.1-py2.py3-none-any.whl (195kB)
        100% |████████████████████████████████| 204kB 3.2MB/s 
    Requirement already satisfied (use --upgrade to upgrade): requests in /usr/local/lib/python2.7/dist-packages (from geocoder)
    Requirement already satisfied (use --upgrade to upgrade): ratelim in /usr/local/lib/python2.7/dist-packages (from geocoder)
    Requirement already satisfied (use --upgrade to upgrade): six in /usr/local/lib/python2.7/dist-packages (from geocoder)
    Requirement already satisfied (use --upgrade to upgrade): click in /usr/local/lib/python2.7/dist-packages (from geocoder)
    Requirement already satisfied (use --upgrade to upgrade): decorator in /usr/local/lib/python2.7/dist-packages/decorator-4.0.10-py2.7.egg (from ratelim-&gt;geocoder)
    Installing collected packages: geocoder
    Successfully installed geocoder-1.15.1

**Then try to import it:**

    import geocoder

    ---------------------------------------------------------------------------
    ImportError                               Traceback (most recent call last)
    &lt;ipython-input-4-603a981d39f2&gt; in &lt;module&gt;()
    ----&gt; 1 import geocoder
    
    ImportError: No module named geocoder

I also tried shutting down the notebook and restarting it without any luck.

**Edit:** I found that using the terminal installs the geocoder package in `/home/ubuntu/.local/lib/python2.7/site-packages` and using a notebook installs it in `/usr/local/lib/python2.7/dist-packages` which is not in the path. `sys.path.append(&#39;/usr/local/lib/python2.7/dist-packages&#39;)` solves the problem for the current session.

So how can I permanently modify the path or tell pip where to install geocoder?

Installing a pip package from within a Jupyter Notebook not working

I have a `.pem` file containing my private key. However, a BitBucket deployment key has this format: 

&gt; ssh-rsa AAAAB3NzaC3yc2EAAAADAQABAAABAQDfZxX2LXOJlo5MP2tLP4fmQyjIAcATwATFKwM6K3mtT7+LKx1jk6YlFlEcj2CFxJHHTy6LCdDqoVzL3iNcD+mDl7NbcNEHytZNJnFQ5lAHPxDVa9ZbLnmP1OlfUvsQS+jAt7yMSwd8gZ6McOJfp9ZUn+r5LLpjYkF+AMQFPsf+6lhSJaOjOTbsA39OJwlnnSO6HF3W2Om+8Bgdpa/E4En5RZTBwFCAvLaaXY3XgN76xCR24TwTWFicBHWeLdADGFXB7OBOv4y805fNGbNKOl3Yb21mG89aUQlYjobeLqImyIrrEhX36hEdMW/t6zZK/1I0QC//uLa+GjJoeuPW4WY3
&gt; ubuntu@Box

It is usually found using: 

`cat ~/.ssh/id_rsa.pub | pbcopy`

How do I extract my public key, in this format, from a `.pem` file? 

How do I get the public key of a pem file?

I have a <code>.pem</code> file containing my private key. However, a BitBucket deployment key has this format:
> ssh-rsa AAAAB3NzaC3yc2EAAAADAQABAAABAQDfZxX2LXOJlo5MP2tLP4fmQyjIAcATwATFKwM6K3mtT7+LKx1jk6YlFlEcj2CFxJHHTy6LCdDqoVzL3iNcD+mDl7NbcNEHytZNJnFQ5lAHPxDVa9ZbLnmP1OlfUvsQS+jAt7yMSwd8gZ6McOJfp9ZUn+r5LLpjYkF+AMQFPsf+6lhSJaOjOTbsA39OJwlnnSO6HF3W2Om+8Bgdpa/E4En5RZTBwFCAvLaaXY3XgN76xCR24TwTWFicBHWeLdADGFXB7OBOv4y805fNGbNKOl3Yb21mG89aUQlYjobeLqImyIrrEhX36hEdMW/t6zZK/1I0QC//uLa+GjJoeuPW4WY3
> ubuntu@Box
It is usually found using:
<code>cat ~/.ssh/id_rsa.pub | pbcopy</code>
How do I extract my public key, in this format, from a <code>.pem</code> file?

I was following [this tutorial][1]:

    node {
      git url: &#39;https://github.com/joe_user/simple-maven-project-with-tests.git&#39;
      ...
    }

However it doesn&#39;t tell how to add credentials. Jenkins does have specific &quot;Credentials&quot; section where you define user user&amp;pass, and then get ID for that to use in jobs, but how do I use that in Pipeline instructions?

I tried with:

    git([url: &#39;git@bitbucket.org:company/repo.git&#39;, branch: &#39;master&#39;, credentialsId: &#39;12345-1234-4696-af25-123455&#39;])
    
no luck:

    stderr: Host key verification failed.
    fatal: Could not read from remote repository.

    Please make sure you have the correct access rights
    and the repository exists.

Is there a way configure the creds in pipeline, or do I have to put SSH-keys to Jenkin&#39;s Linux user&#39;s .ssh/authorized_keys file?

In ideal world I&#39;d like to have a repository for pipeline jobs and repo-keys, then launch Docker Jenkins, and dynamically add these jobs and keys there without having to configure anything in Jenkins Console.


  [1]: https://jenkins.io/doc/pipeline/

Checkout Jenkins Pipeline Git SCM with credentials?

I have PostgreSQL 9.3 installed on a server running Ubuntu Server 14.04.

If I ssh into the server via terminal, I&#39;m able to connect with psql. But when I try to configure pgAdmin III to do the remote connection, I get:

&gt; Server doesn&#39;t listen The server doesn&#39;t accept connections: the
&gt; connection library reports  could not connect to server: Connection
&gt; refused Is the server running on host &quot;172.24.3.147&quot; and accepting
&gt; TCP/IP connections on port 5432?

When I run on the server `service postgresql status` it gives me:

    9.3/main (port 5432): online

So of course I&#39;m missing something important here.

EDIT

When running `netstat -na` on the server, I get (relevant portion, I guess):

    Active Internet connections (servers and established)
    Proto Recv-Q Send-Q Local Address           Foreign Address         State      
    tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN     
    tcp        0      0 127.0.0.1:5432          0.0.0.0:*               LISTEN     
    tcp        0      0 172.24.3.147:22         172.24.3.240:61950      ESTABLISHED
    tcp        0      0 172.24.3.147:22         172.24.3.240:60214      ESTABLISHED



Can&#39;t connect to Postgresql on port 5432

I am writing a program using pysftp, and it wants to verify the SSH host Key against `C:\Users\JohnCalvin\.ssh\known_hosts`.

Using PuTTY, the terminal program is saving it to the Registry `[HKEY_CURRENT_USER\Software\SimonTatham\PuTTY\SshHostKeys]`.

How do I reconcile the difference between pysftp and PuTTY?

My code is:

```python
import pysftp as sftp

def push_file_to_server():
    s = sftp.Connection(host=&#39;138.99.99.129&#39;, username=&#39;root&#39;, password=&#39;*********&#39;)
    local_path = &quot;testme.txt&quot;
    remote_path = &quot;/home/testme.txt&quot;

    s.put(local_path, remote_path)
    s.close()

push_file_to_server()
```

The error response I am receiving is:

```none
E:\Program Files (x86)\Anaconda3\lib\site-packages\pysftp\__init__.py:61:
UserWarning: Failed to load HostKeys from C:\Users\JohnCalvin\.ssh\known_hosts.  You will need to explicitly load HostKeys (cnopts.hostkeys.load(filename)) or disableHostKey checking (cnopts.hostkeys = None).
 warnings.warn(wmsg, UserWarning)
Traceback (most recent call last): 
  File &quot;E:\OneDrive\Python\GIT\DigitalCloud\pysftp_tutorial.py&quot;, line 14, in &lt;module&gt;
    push_file_to_server()
  File &quot;E:\OneDrive\Python\GIT\DigitalCloud\pysftp_tutorial.py&quot;, line 7, in push_file_to_server
    s = sftp.Connection(host=&#39;138.99.99.129&#39;, username=&#39;root&#39;, password=&#39;********&#39;) 
  File &quot;E:\Program Files (x86)\Anaconda3\lib\site-packages\pysftp\__init__.py&quot;, line 132, in __init__
    self._tconnect[&#39;hostkey&#39;] = self._cnopts.get_hostkey(host)   
  File &quot;E:\Program Files (x86)\Anaconda3\lib\site-packages\pysftp\__init__.py&quot;, line 71, in get_hostkey
    raise SSHException(&quot;No hostkey for host %s found.&quot; % host) paramiko.ssh_exception.SSHException: No hostkey for host 138.99.99.129 found.
Exception ignored in: &lt;bound method Connection.__del__ of &lt;pysftp.Connection object at 0x00000222FF3A6BE0&gt;&gt;
Traceback (most recent call last):
  File &quot;E:\Program Files (x86)\Anaconda3\lib\site-packages\pysftp\__init__.py&quot;, line 1013, in __del__
    self.close()  
  File &quot;E:\Program Files (x86)\Anaconda3\lib\site-packages\pysftp\__init__.py&quot;, line 784, in close
    if self._sftp_live:
AttributeError: &#39;Connection&#39; object has no attribute &#39;_sftp_live&#39;
```


Verify host key with pysftp

Using ubuntu tusty, there is a service running on a remote machine, that I can access via port forwarding through an ssh tunnel from `localhost:9999`.

I have a docker container running. I need to access that remote service via the host&#39;s tunnel, from within the container.


I tried tunneling from the container to the host with `-L 9000:host-ip:9999` , then accessing the service through `127.0.0.1:9000` from within the container fails to connect. To check wether the port mapping was on, I tried
```
nc -luv -p 9999 # at host
nc -luv -p 9000 # at container
```

following [this, parag. 2][1] but there was no perceived communication, even when doing 
```
nc -luv host-ip -p 9000 
```  at the container

I also tried mapping the ports via `docker run -p 9999:9000 ` , but this reports that the bind failed because the host port is already in use (from the host tunnel to the remote machine, presumably).

So my questions are

1 - How will I achieve the connection?  Do I need to setup an ssh tunnel to the host, or can this be achieved with the docker port mapping alone?

2 - What&#39;s a quick way to test that the connection is up? Via bash, preferably.

Thanks.
  [1]: http://www.binarytides.com/netcat-tutorial-for-beginners/

access host&#39;s ssh tunnel from docker container

My problem is that I can&#39;t push or fetch from GitLab. However, I can clone (via HTTP or via SSH). I get this error when I try to push :

&gt; Permission denied (publickey) fatal : Could not read from remote repository

From all the threads I&#39;ve looked, here is what I have done :

 - Set up an SSH key on my computer and added the public key to GitLab
 - Done the config --global for username and email
 - Cloned via SSH and via HTTP to check if it would resolve the issue
 - Done the ssh -T git@gitlab.com command

If you have any insight about how to resolve my issue, it would be greatly appreciated.

Getting permission denied (public key) on gitlab

Can some one help me understand how an RSA key literally is stored in these formats? I would like to know the difference between the PKCS formats vs Encodings(DER, PEM). From what I understand PEM is more human readable. Is PEM/DER for keys/certs similar to UTF-8/16 for characters? What is the significance of DER/PEM? Sorry too many questions but fed up googling and getting vague answers. Thanks.

PKCS#1 and PKCS#8 format for RSA private key

I get an error when pip builds wheels for the cryptography package.

Error:

[![Error][1]][1]

```
LINK : fatal error LNK1181: cannot open input file &#39;libssl.lib&#39;
  error: command &#39;C:\\Program Files (x86)\\Microsoft Visual Studio\\2017\\BuildTools\\VC\\Tools\\MSVC\\14.16.27023\\bin\\HostX86\\x86\\link.exe&#39; failed with exit status 1181
  ----------------------------------------
  ERROR: Failed building wheel for cryptography
  Running setup.py clean for cryptography
Failed to build cryptography
ERROR: Could not build wheels for cryptography which use PEP 517 and cannot be installed directly
```

I have already installed OpenSSL and set the environment variables as suggested in [this post][2] yet the problem persists. My setup details: 

 - System - Windows 10 
 - Python - 3.8  
 - Pip - 19.3.1

  [1]: https://i.stack.imgur.com/2F20z.png
  [2]: https://stackoverflow.com/a/22210069/7199817

ERROR: Could not build wheels for cryptography which use PEP 517 and cannot be installed directly

My organization is switching from Bitbucket to Github for project management. Today, I was trying to transfer our most recent project from Bitbucket to Github, by using SourceTree. I added a second remote repository to the project (using the URL of the destination repository on Github), brought everything up to date, and then attempted to push the code to the repository. A box popped up, asking for the password to my Github account. I entered in my (correct) password, and clicked &#39;OK&#39;, and the dialog box popped up again. I entered in my password (correctly) again, and it did the same thing.

My username is correctly identified, my password is correct, and I tried updating SourceTree because I had heard that it was an issue with a previous version. The problem persists.

I am using SourceTree 2.3.1

SourceTree keeps asking for Github password

I am trying to create a Jenkins workflow using a Jenkinsfile. All I want it to do is monitor the &#39;develop&#39; branch for changes. When a change occurs, I want it to git tag and merge to master. I am using the GitSCM Step but the only thing that it appears to support is git clone. I don&#39;t want to have to shell out to do the tag / merge but I see no way around it. Does anyone know if this is possible? I am using BitBucket (on-prem) for my Git server.

Is it possible to Git merge / push using Jenkins pipeline

I have a single repository in which I have two user groups:

- Administrators
- HTML/UI Developers

I do not wish to give read/write access of my `master` branch to my HTML developers as they do not need to work on it and should not be misusing the core code.

Though they need to work on their own branch `ui-developers`. How do I do this on Git?

P.S.: I am using Bitbucket


&lt;hr/&gt;

I had posted this question when I was extremely new to coding and Git. After two years of experience, I now know that Git doesn&#39;t allow to restrict READ access for any particular branch. But services like Bitbucket, GitLab, and GitHub allow you to put write and merge restrictions to branches.

Also, I shifted to GitLab six months back :)









How to restrict access to the master branch in Git

I&#39;m trying to commit the changes to my repository but I receive the error below:

    git -c diff.mnemonicprefix=false -c core.quotepath=false commit -q -F C:\Users\Contronym\AppData\Local\Temp\bkdweixb.mnu
    fatal: cannot lock ref &#39;HEAD&#39;: unable to resolve reference HEAD: Invalid argument
    
    Completed with errors, see above.

I&#39;m using bitbucket and SourceTree.

What&#39;s the reason for this commit failing? I was able to commit just fine the last 3 commits over the past week. Then, all of a sudden, I receive this error.

**EDIT**

I ran `git gc` and these are the results:

    $ git gc
    error: bad ref for HEAD
    error: bad ref for HEAD
    error: inflate: data stream error (unknown compression method)
    fatal: loose object 53b65bd9b4fec7f6a7b0b3313c68199a18804327 (stored in .git/objects/53/b65bd9b4fec7f6a7b0b3313c68199a18804327) is corrupt
    error: failed to run repack

I checked the directory `.git/objects/53/b65bd9b4fec7f6a7b0b3313c68199a18804327` but that doesn&#39;t exist. There&#39;s two other files there, but `b65bd9b4fec7f6a7b0b3313c68199a18804327` doesn&#39;t exist.



Git cannot lock ref &#39;HEAD&#39;: unable to resolve reference HEAD

I have created an app password as explained [here][1]

But now, how do I access the repository using this app password?&lt;br&gt;What will be the url?&lt;br&gt;Can someone direct me to a page showing an example please?

The below is a code for github. How do I do it for bitbucket?

    var githubToken = &quot;[token]&quot;;
    var url = &quot;https://github.com/[username]/[repository]/archive/[sha1|tag].zip&quot;;
    var path = @&quot;[local path]&quot;;


    using (var client = new System.Net.Http.HttpClient())
    {
        var credentials = string.Format(System.Globalization.CultureInfo.InvariantCulture, &quot;{0}:&quot;, githubToken);
        credentials = Convert.ToBase64String(System.Text.Encoding.ASCII.GetBytes(credentials));
        client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue(&quot;Basic&quot;, credentials);
        var contents = client.GetByteArrayAsync(url).Result;
        System.IO.File.WriteAllBytes(path, contents);
    }

## Update

Go to **Personal Settings** and then **[App Passwords](https://bitbucket.org/account/settings/app-passwords/)** as shown below.

[![Create Bitbucket App Password][2]][2]


  [1]: https://confluence.atlassian.com/bitbucket/app-passwords-828781300.html
  [2]: https://i.stack.imgur.com/Situv.png

How to access bitbucket using app password

I&#39;m encrypting data in my app using a RSA keypair that I am storing in the Android keystore.

I&#39;ve been seeing `NullPointerException`s in the Play Store, but I have not been able to reproduce them:

    java.lang.NullPointerException: chain == null
    	at java.security.KeyStore$PrivateKeyEntry.&lt;init&gt;(KeyStore.java:1205)
    	at java.security.KeyStoreSpi.engineGetEntry(KeyStoreSpi.java:374)
    	at java.security.KeyStore.getEntry(KeyStore.java:644)
    	at MyClass.getKeyStoreEntry(MyClass.java:111)

The source code to create the key pair

    Calendar start = Calendar.getInstance();
    start.setTimeInMillis(0);
    Calendar end = Calendar.getInstance();
    end.set(Calendar.YEAR, 3000);
    
    KeyPairGeneratorSpec.Builder keySpecBuilder = new KeyPairGeneratorSpec.Builder(context)
        .setAlias(keyName)
        .setSubject(new X500Principal(&quot;CN=&quot; + keyName))
        .setSerialNumber(BigInteger.TEN)
        .setStartDate(start.getTime())
        .setEndDate(end.getTime())
        .setKeySize(RSA_KEY_SIZE);

    KeyPairGeneratorSpec spec = keySpecBuilder.build();
    KeyPairGenerator gen = KeyPairGenerator.getInstance(&quot;RSA&quot;, &quot;AndroidKeyStore&quot;);
    gen.initialize(spec);
    gen.generateKeyPair();

And then to retrieve the key:

    private KeyStore.PrivateKeyEntry getKeyStoreEntry() {
        KeyStore keyStore = KeyStore.getInstance(ANDROID_KEY_STORE);
        keyStore.load(null);
    
        if (!keyStore.containsAlias(keyName)) {
            throw new KeyNotFoundException();
        }
        return (KeyStore.PrivateKeyEntry) keyStore.getEntry(keyName, null);
    }

This is only happening when I make use of the `KeyPairGeneratorSpec` on API level 19-22. The 23+ implementation works fine.

I [do not have another key with the same name][1] and I also have not [deleted the key][2].


  [1]: https://stackoverflow.com/questions/23977407/android-4-3-keystore-chain-null-while-trying-to-retrieve-keys
  [2]: https://stackoverflow.com/questions/37094464/android-keystore-issue-keystore-getentryalias-null-returns-null-sometimes

Chain is null when retrieving private key

One of our Apps [`github-backup`](https://github.com/dwyl/github-backup) requires the use of an RSA Private Key as an Environment Variable.

Simply attempting to export the key it in the terminal e.g:
```text
export PRIVATE_KEY=-----BEGIN RSA PRIVATE KEY-----
MIIEpAIBAAKCAQEA04up8hoqzS1+
...
l48DlnUtMdMrWvBlRFPzU+hU9wDhb3F0CATQdvYo2mhzyUs8B1ZSQz2Vy==
-----END RSA PRIVATE KEY-----
```

Does not work ... because of the line breaks.

I did a bit of googling but did not find a workable solution ... &lt;br /&gt;
e.g: https://stackoverflow.com/questions/43082918/how-to-sett-multiline-rsa-private-key-environment-variable-for-aws-elastic-beans

![image](https://user-images.githubusercontent.com/194400/37850998-2f87b140-2ed5-11e8-8350-c003c2768e1f.png)

Error:
```
-----END RSA PRIVATE KEY-----&#39;: not a valid identifier
```

followed the instructions in: 
http://blog.vawter.com/2016/02/10/Create-an-Environment-Variable-from-a-Private-Key 

Created a file called `keytoenvar.sh` with the following lines:

    #!/usr/bin/env bash
    file=$2
    name=$1
    export $name=&quot;$(awk &#39;BEGIN{}{out=out$0&quot;\n&quot;}END{print out}&#39; $file| sed &#39;s/\n$//&#39;)&quot;


![image](https://user-images.githubusercontent.com/194400/37851077-76edb4da-2ed5-11e8-8872-ea75be0217a0.png)
then ran the following command:

    source keytoenvar.sh PRIVATE_KEY ./gitbu.2018-03-23.private-key.pem

That _works_ but it seems like a &quot;_long-winded_&quot; approach ... &#129300; 

Does anyone know of a _simpler_ way of doing this? &lt;br /&gt;
(_I&#39;m hoping for a &quot;**beginner friendly**&quot; solution without too many &quot;steps&quot;..._) 

Content Type	Original Author	Original Content on Stackoverflow
Question	sdgfsdh	View Question on Stackoverflow
Solution 1 - Ssh	JazzCat	View Answer on Stackoverflow
Solution 2 - Ssh	Lilanga	View Answer on Stackoverflow

How do I get the public key of a pem file?

Ssh Problem Overview

Ssh Solutions

Solution 1 - Ssh

Solution 2 - Ssh

Installing a pip package from within a Jupyter Notebook not working

Batch Normalization in Convolutional Neural Network

Attributions