### Syntax 1

    */5+2 * * * * 1st-script
    */5+4 * * * * 2nd-script

For future reference take a look at this online [Cron Job Generator][1].

### Syntax 2

Since there are several reports that the `+` syntax is not working on Ubuntu 14.04, here&#39;s a variation:

    2-59/5 * * * * 1st-script
    4-59/5 * * * * 2nd-script

This will result in the 1st script to run every 5 minutes starting with an offset of 2 minutes at the beginning of each hour and the 2nd script to behave the same with an offset of 4 minutes.

  [1]: https://www.generateit.net/cron-job/

or

    */5 * * * * sleep 120; ( first_script.sh &amp; ) ; sleep 120 ; second_script.sh

nice thing about this approach is that you can let crontab start things at times other then minute boundaries (like 30 seconds after the hour)

    */5+1 * * * * first_script.sh

To run every five minutes, but offset one minute


I needed similar thing - to execute script every 5 minutes starting from third minute of an hour. I doubted above solutions (because website crontab.guru was convincing me about invalid syntax) and so my colleague told me to specify minutes directly like this:

3,8,13,18,23,28,33,38,43,48,53,58 * * * *

Its list of concrete minutes.

Can someone please explain what the main differences between these two data structures are?  I&#39;ve been trying to find a source online that highlights the differences/similarities, but I haven&#39;t found anything too informative.  In what cases would one be preferred over the other?  What practical situations make one &quot;better&quot; to use than the other?

Difference between red-black trees and AVL trees

In my Angular.js application, I&#39;m running some asynchronous operation. Before it starts I cover the application with a modal div, then once the operation is complete, I need to remove the div, whether the operation was successful or not.

Currently I have this:

&lt;!-- language: lang-js --&gt;

    LoadingOverlay.start();	
    Auth.initialize().then(function() {
        LoadingOverlay.stop();
    }, function() {
        LoadingOverlay.stop(); // Code needs to be duplicated here
    })

It works well, however I would prefer to have something cleaner like this pseudo-code:

&lt;!-- language: lang-js --&gt;

    LoadingOverlay.start();	
    Auth.initialize().finally(function() { // *pseudo-code* - some function that is always executed on both failure and success.
        LoadingOverlay.stop();
    })

I assume it&#39;s quite a common problem, so I was thinking it could be done but cannot find anything in the doc. Any idea if it can be done?

How to always run some code when a promise is fulfilled in Angular.js

I would like to have a script run every 5 minutes let&#39;s say starting from 13:02 so I can have another script runs every 5 minutes but starting from 13:04 so the second script runs two minutes after the start of the first job. How can I achieve this?

How can I run a cron job every 5 minutes starting from a time other than 0 minutes?

<p>I would like to have a script run every 5 minutes let's say starting from 13:02 so I can have another script runs every 5 minutes but starting from 13:04 so the second script runs two minutes after the start of the first job. How can I achieve this?</p>


I just installed node and npm through the package on nodejs.org, and whenever I try to search or install something with npm, it throws the following error unless I sudo the command.  I have a feeling this is a permissions issue?  I am already the admin.

    npm ERR! Error: EACCES, open &#39;/Users/chietala/.npm/-/all/.cache.json&#39;
    npm ERR!  { [Error: EACCES, open &#39;/Users/chietala/.npm/-/all/.cache.json&#39;]
    npm ERR!   errno: 3,
    npm ERR!   code: &#39;EACCES&#39;,
    npm ERR!   path: &#39;/Users/chietala/.npm/-/all/.cache.json&#39; }
    npm ERR! 
    npm ERR! Please try running this command again as root/Administrator.
    
    npm ERR! System Darwin 12.2.0
    npm ERR! command &quot;node&quot; &quot;/usr/local/bin/npm&quot; &quot;search&quot; &quot;bower&quot;
    npm ERR! cwd /Users/chietala
    npm ERR! node -v v0.10.4
    npm ERR! npm -v 1.2.18
    npm ERR! path /Users/chietala/.npm/-/all/.cache.json
    npm ERR! code EACCES
    npm ERR! errno 3
    npm ERR! stack Error: EACCES, open &#39;/Users/chietala/.npm/-/all/.cache.json&#39;
    npm ERR! 
    npm ERR! Additional logging details can be found in:
    npm ERR!     /Users/chietala/npm-debug.log
    npm ERR! not ok code 0

How to fix npm throwing error without sudo

I am encrypting data with openSSL using RSA encryption, which works fine. My understanding of RSA is, that encrypting the same data with the same public key will always give you the same result ([as stated here][1] or [here][2]). 

However, using openssl I get different results every time I repeat the encryption. 
For example:  

    ➜  ~  echo &#39;30&#39; | openssl rsautl -encrypt -inkey pub.pem -pubin  | shasum
          11b6e058273df1ebe0be5e0596e07a6c51724ca0  -

    ➜  ~  echo &#39;30&#39; | openssl rsautl -encrypt -inkey pub.pem -pubin  | shasum
          05cb82595f7429ef196189f4e781088597d90eee  -

So why is the output not unique? Is it because I got the RSA encryption wrong or because openssl does some additional magic? 


Actually I am trying to design a database which stores only RSA encrypted data. I would like to do searches on the hashsums of the encrypted information, which is impossible if the encryption procedure by itself is not unique. 
 

  [1]: http://www.learner.org/courses/mathilluminated/units/1/textbook/07.php
  [2]: https://stackoverflow.com/questions/5883451/are-rsa-signatures-unique

Why does RSA encrypted text give me different results for the same text

I see how to pipe stuff together using Node.js streams, but how do you pipe multiple scripts together using the Unix `|`, given that some of these scripts can be async?

    $ ./a.js | ./b.js

Example:

**a.js** (chmod 0755)

    #!/usr/bin/env node

    setTimeout(function(){
      console.log(JSON.stringify({ foo: &#39;bar&#39; }));
    }, 10);

**b.js** (chmod 0755)

    #!/usr/bin/env node

    console.log(process.argv);

This is the output:

    $ ./a.js | ./b.js
    [ &#39;node&#39;, &#39;/Users/viatropos/tests/b.js&#39; ]

    events.js:72
            throw er; // Unhandled &#39;error&#39; event
                  ^
    Error: write EPIPE
        at errnoException (net.js:883:11)
        at Object.afterWrite (net.js:700:19)

At first glance it seems like there&#39;s a lot going wrong, so not really sure where to start. Is there a way to get this to work? The end goal is to be able to take the `console.log` output from `./a.js` and use it in `./b.js`. The reason is, most of the time these scripts will be run one at a time, but sometimes it would be nice to be able to pipe them together, so ideally the system should be able to handle both cases.

How to pipe Node.js scripts together using the Unix | pipe (on the command line)?

I have used threading before in my applications and know its concepts well, but recently in my operating system lecture I came across fork(). Which is something similar to threading.

I google searched difference between them and I came to know that:

 1. Fork is nothing but a new process that looks exactly like the old or the parent process but still it is a different process with different process ID and having  it’s own memory.
 2. Threads are light-weight process which have less overhead

But, there are still some questions in my mind.

 1. When should you prefer fork() over threading and vice-verse?
 2. If I want to call an external application as a child, then should I use fork() or threads to do it?
 3. While doing google search I found people saying it is bad thing to call a fork() inside a thread. why do people want to call a fork() inside a thread when they do similar things?
 4. Is it True that fork() cannot take advantage of multiprocessor system because parent and child process don&#39;t run simultaneously?


Forking vs Threading

In the header of a Bash script, what&#39;s the difference between those two statements:

 1.  `#!/usr/bin/env bash`

 2.  `#!/usr/bin/bash`

When I consulted the `env` [man page](https://linux.die.net/man/1/env), I get this definition:

&lt;!-- language: none --&gt;

     env - run a program in a modified environment

What does it mean?


What is the difference between &quot;#!/usr/bin/env bash&quot; and &quot;#!/usr/bin/bash&quot;?

I&#39;m learning node.js and just set up an empty Linux Virtual Machine and installed node.

I&#39;m running a function constantly every minute 

    var request = require(&#39;request&#39;)
    var minutes = 1, the_interval = minutes * 60 * 1000

    setInterval(function() {
        // Run code
      })
    }, the_interval);


And considering adding some other functions based on current time. - (e.g. run function if dateTime = Sunday at noon)

My question is are there any disadvantages to running a set up like this compared to a traditional cron job set up?

Keep in mind I have to run this function in node every minute anyways.

Set Interval in Node.js vs. Cron Job?

I am defining scheduled jobs with cron style patterns in Spring, using the `@Scheduled` annotation.

The cron pattern is stored in a config properties file. Actually there are two properties files: one default config, and one profile config that is environment dependent (e.g. dev, test, prod customer 1, prod customer 2 etc.) and overrides some of the default values.

I configured a property placeholder bean in my spring context which allows me to use `${}` style placeholders to import values from my properties files.

The job beans looks like this:

    @Component
    public class ImagesPurgeJob implements Job {
    	
    	private Logger logger = Logger.getLogger(this.getClass());
    
    	@Override
        @Transactional(readOnly=true)
        @Scheduled(cron = &quot;${jobs.mediafiles.imagesPurgeJob.schedule}&quot;)
    	public void execute() {
    		//Do something
                //can use DAO or other autowired beans here
    	}
    }

Relevant parts of my context XML :

    &lt;!-- Enable configuration of scheduled tasks via annotations --&gt;
        &lt;task:annotation-driven/&gt;
    
    &lt;!-- Load configuration files and allow &#39;${}&#39; style placeholders --&gt;
        &lt;bean class=&quot;org.springframework.context.support.PropertySourcesPlaceholderConfigurer&quot;&gt;
            &lt;property name=&quot;locations&quot;&gt;
                &lt;list&gt;
                    &lt;value&gt;classpath:config/default-config.properties&lt;/value&gt;
                    &lt;value&gt;classpath:config/environment-config.properties&lt;/value&gt;
                &lt;/list&gt;
            &lt;/property&gt;
            &lt;property name=&quot;ignoreUnresolvablePlaceholders&quot; value=&quot;true&quot;/&gt;
            &lt;property name=&quot;ignoreResourceNotFound&quot; value=&quot;false&quot;/&gt;
        &lt;/bean&gt;


I really like this. It&#39;s quite simple and clean with minimal XML.

However I have one more requirement: some of these jobs can be totally disabled in some cases.

So, before I used Spring to manage them I created them manually and there is a boolean parameter along with the cron parameter in the config files, to specify if the job has to be enabled or not:

    jobs.mediafiles.imagesPurgeJob.enable=true or false
    jobs.mediafiles.imagesPurgeJob.schedule=0 0 0/12 * * ?

How can I use this parameter in Spring to conditionally create or just plainly ignore the bean, depending on this config parameter?

One obvious workaround would be to define a cron pattern that would never evaluate, so the job is never executed. But the bean would still be created and the config would be a bit obscure, so I feel there must be a better solution.

How to conditionally enable or disable scheduled jobs in Spring?

I&#39;m new to using cron job. I don&#39;t even know how to write it. I have tried to search from internet, but I still don&#39;t understand it well. I want to create a cron job that will execute my code every minute. I&#39;m using PHP to create it. It is not working.

**Example**

**run.php**  *(Code that will be executed every minute)*

    &lt;?php

    echo &quot;This code will run every minute&quot;;

    ?&gt;

**cron.php**

    &lt;?php

    $path = dirname(__FILE__);
    $cron = $path . &quot;/run.php&quot;;
    echo exec(&quot;***** php -q &quot;.$cron.&quot; &amp;&gt; /dev/null&quot;);

    ?&gt;

*Suppose that these two files are in the same folder.*

Is the code that I did wrong? If wrong, please kindly tell me how to fix it.


How to create cron job using PHP?

In crontab does the Day of the Week field run from `0 - 6` or `1 -7`?

I am seeing conflicting information on this.  wikipedia states `0-6` and other sites I have seen are `1-7`.

Also what would be the implication or either using `0` or `7` incorrectly?  i.e. would the cron still run?

Crontab Day of the Week syntax

How can I run a cron job every 15 mins on Jenkins?

This is what I&#39;ve tried : 

On Jenkins I have a job set to run every 15 mins using this cron syntax  :

    14 * * * *

But the job executes every hour instead of 15 mins.

I&#39;m receiving a warning about the format of the cron syntax : 

    Spread load evenly by using ‘H * * * *’ rather than ‘14 * * * *’

Could this be the reason why the cron job executes every hour instead of 15 mins ?

Content Type	Original Author	Original Content on Stackoverflow
Question	RazorHead	View Question on Stackoverflow
Solution 1 - Unix	Rolando Isidoro	View Answer on Stackoverflow
Solution 2 - Unix	Emile Aben	View Answer on Stackoverflow
Solution 3 - Unix	dave	View Answer on Stackoverflow
Solution 4 - Unix	Ales	View Answer on Stackoverflow

How can I run a cron job every 5 minutes starting from a time other than 0 minutes?

Unix Problem Overview

Unix Solutions

Solution 1 - Unix

Syntax 1

Syntax 2

Solution 2 - Unix

Solution 3 - Unix

Solution 4 - Unix

How to always run some code when a promise is fulfilled in Angular.js

Difference between red-black trees and AVL trees

Attributions