The manpage of `logrotate.conf` contains an important advice for the *hourly* option:

&gt; Log files are rotated every hour. **Note that usually logrotate is configured to be run by cron daily. You have to change this configuration and run logrotate hourly to be able to really  rotate logs hourly.**

As pointed out by [yellow1pl][1] the solution is to copy the file `/etc/cron.daily/logrotate` into the `/etc/cron.hourly/` directory. This works at least for Debian and possibly some Debian derivates.


  [1]: https://stackoverflow.com/a/25485416/1340631

There is `/etc/cron.daily/logrotate` script for daily logrotates. However there is no such script by default in `/etc/cron.hourly/` directory. Copy this script and it should work fine.

I have the following log table for user messages (simplified form) in Postgres 9.2:

    CREATE TABLE log (
        log_date DATE,
        user_id  INTEGER,
        payload  INTEGER
    );

It contains up to one record per user and per day. There will be approximately 500K records per day for 300 days. payload is ever increasing for each user (if that matters).

I want to efficiently retrieve the latest record for each user before a specific date. My query is:

    SELECT user_id, max(log_date), max(payload) 
    FROM log 
    WHERE log_date &lt;= :mydate 
    GROUP BY user_id

which is extremely slow. I have also tried:

    SELECT DISTINCT ON(user_id), log_date, payload
    FROM log
    WHERE log_date &lt;= :mydate
    ORDER BY user_id, log_date DESC;

which has the same plan and is equally slow.

So far I have a single index on `log(log_date)`, but doesn&#39;t help much.

And I have a `users` table with all users included. I also want to retrieve the result for some some users (those with `payload &gt; :value`).

Is there any other index I should use to speed this up, or any other way to achieve what I want?

Optimize GROUP BY query to retrieve latest row per user

How to make transparent or translucent ActionBar like Google Play that fades in or out when scrolling using `windowActionBarOverlay`? 

**Check the following screenshots**

[![**enter image description here**][2]][3]





  [1]: https://developer.android.com/training/basics/actionbar/overlaying.html
  [2]: http://i.stack.imgur.com/vKaw3l.jpg
  [3]: http://i.stack.imgur.com/vKaw3.png
  [4]: http://stackoverflow.com/questions/6749261/custom-translucent-android-actionbar

How to make a ActionBar like Google Play that fades in when scrolling

I tried to set up a log rotation of logs files located at /tmp/hr_logs/. For setting up, I used logrotate in linux and I&#39;m able to rotate it on daily basis using the following config in my /etc/logrotate.conf

      /tmp/hr_logs {
      daily
      rotate 4


With this config, file will rotate on daily basis and system will keep 4 copies of the log file appended with date [format: -YYYYMMDD]

Now, I trying to set up a different set of log files which I need to make rotate on hourly basis and for it, i have done the configuration in logrotate.conf:

      /tmp/last_logs {
      hourly
      rotate 4

But this is not at all working? Can anyone please guide me on this please?





Hourly rotation of files using logrotate?

I tried to set up a log rotation of logs files located at /tmp/hr_logs/. For setting up, I used logrotate in linux and I'm able to rotate it on daily basis using the following config in my /etc/logrotate.conf
<pre><code class="hljs language-bash"> /tmp/hr_logs {
 daily
 rotate 4
</code></pre>
With this config, file will rotate on daily basis and system will keep 4 copies of the log file appended with date [format: -YYYYMMDD]
Now, I trying to set up a different set of log files which I need to make rotate on hourly basis and for it, i have done the configuration in logrotate.conf:
<pre><code class="hljs language-bash"> /tmp/last_logs {
 hourly
 rotate 4
</code></pre>
But this is not at all working? Can anyone please guide me on this please?

I&#39;m trying to remove all the dateed logs except the most recent. Before I execute a script to remove the files, I want to of course test my commands to make sure I&#39;m bringing up accurate results.

When executing these commands the date is:

    Sep  1 00:53:44 AST 2014

Directory Listing:

    Aug 27 23:59 testfile.2014-08-27.log
    Aug 28 23:59 testfile.2014-08-28.log
    Aug 29 23:59 testfile.2014-08-29.log
    Aug 30 23:59 testfile.2014-08-30.log
    Aug 31 23:59 testfile.2014-08-31.log
    Sep  1 00:29 testfile.log

I thought -mtime +1 was supposed to list all files over a day old. Why isn&#39;t the 8-30.log one listed?

    find . -type f -mtime +1 -name &quot;testfile*log&quot;
    ./testfile.2014-08-27.log
    ./testfile.2014-08-28.log
    ./testfile.2014-08-29.log

This is the desired effect, but it was just trial and error. What is this 0 saying?

    find . -type f -mtime +0 -name &quot;testfile*log&quot;
    ./testfile.2014-08-30.log
    ./testfile.2014-08-27.log
    ./testfile.2014-08-28.log
    ./testfile.2014-08-29.log



Explaining the &#39;find -mtime&#39; command

I want to have `tcpdump` write raw packet data into a file and also display packet analysis into standard output as the packets are captured (by analysis I mean the lines it displays normally when `-w` is missing).
Can anybody please tell me how to do that?

How can I have tcpdump write to file and standard output the appropriate data?

I&#39;m using putty on a Linux machine. My usual method for searching in vi is entering the slash &lt;kbd&gt;/&lt;/kbd&gt;, then my search string, enter, then go through all the matches by &lt;kbd&gt;n&lt;/kbd&gt; or &lt;kbd&gt;shift&lt;/kbd&gt; + &lt;kbd&gt;n&lt;/kbd&gt;.

I was wondering if vi had a feature like Eclipse&#39;s Incremental Search (&lt;kbd&gt;ctrl&lt;/kbd&gt; + &lt;kbd&gt;j&lt;/kbd&gt;), wherein as I type, it jumps to the next logical match. I think one of my office mates used to do it but I&#39;m not sure.

Vim incremental search

What is the difference between ampersand and semicolon in Linux [Bash][1]?

For example,

    $ command1 &amp;&amp; command2

vs

    $ command1; command2

  [1]: http://en.wikipedia.org/wiki/Bash_%28Unix_shell%29


What is the difference between double-ampersand (&amp;&amp;) and semicolon (;) in Linux Bash?

I&#39;m trying to find files with specific extensions. 
For example, I want to find all .pdf and .jpg files that&#39;s named Robert

I know I can do this command 

    $ find . -name &#39;*.h&#39; -o -name &#39;*.cpp&#39;

but I need to specify the name of the file itself besides the extensions. 
I just want to see if there&#39;s a possible way to avoid writing the file name again and over again
Thank you !

Recursively find files with a specific extension

I&#39;m running a PHP script in a cronjob and I want to send emails every 5 minutes

My current (crontab) cronjob:

    10 * * * * /usr/bin/php /mydomain.in/cromail.php &gt; /dev/null 2&gt;&amp;1

The cronmail.php is as follows:

    &lt;?php
    $from = &#39;D&#39;; // sender
    $subject = &#39;S&#39;;
    $message = &#39;M&#39;;
    $message = wordwrap($message, 70);
    mail(&quot;myemail@gmail.com&quot;, $subject, $message, &quot;From: $from\n&quot;);
    ?&gt;

But I&#39;ve not received an email in 30 minutes with this configuration.

How to run a cronjob every X minutes?

I&#39;m trying to have my code execute on a fixed schedule, based on a Spring cron expression. I would like the code to be executed every day at 1:01:am. I tried the following expression, but this didn&#39;t fire up for me. What&#39;s wrong with the syntax here?

    @Scheduled(cron = &quot;0 1 1 ? * *&quot;)
    public void resetCache() {
        // ...
    }



Spring cron expression for every day 1:01:am

I would like to run a python cron job inside of a docker container in detached mode. My set-up is below:

My python script is test.py

    #!/usr/bin/env python
    import datetime
    print &quot;Cron job has run at %s&quot; %datetime.datetime.now()

My cron file is my-crontab

    * * * * * /test.py &gt; /dev/console

and my Dockerfile is 

    FROM ubuntu:latest
    RUN apt-get update &amp;&amp; apt-get install -y software-properties-common python-software-properties &amp;&amp; apt-get update

    RUN apt-get install -y python cron
    ADD my-crontab /
    ADD test.py /
    RUN chmod a+x test.py

    RUN crontab /my-crontab
    ENTRYPOINT cron -f

What are the potential problems with this approach? Are there other approaches and what are their pros and cons?

Running cron python jobs within docker

I&#39;ve recently tried running a cron job from within a linked docker container and run into an issue. My main docker container is linked to a postgres container and its port number is set as an environment variable by docker upon the containers creation. This environment variable is not set in ~/.profile or any other source file that I could load when running my cron job. How can I then access these environment variables from my cron job?

Thanks!

How can I access Docker set Environment Variables From a Cron Job

How can I run a job created in Jenkins every one minute ? Am I missing anything?

PS: I&#39;m trying not to use: ***/1 * * * ***

![enter image description here][1]
![enter image description here][2]


  [1]: http://i.stack.imgur.com/cBCvw.jpg
  [2]: http://i.stack.imgur.com/JEBqz.jpg

Run a Jenkins job every one minute using H/1 * * * *

I installed MariaDB on CentOS 7 but I had some problems with some configuration, now it is completely misconfigured. 

Thus, I wanted to remove the MariaDB with “yum remove mariadb mariadb-server”, after that I reinstalled it with “yum install mariadb mariadb-server”.

Unfortunately, the configuration remains. It seems as if yum remove don’t delete all MariaDB Config-Files.

How can I remove MariaDB completely from CentOS 7?


Completely remove MariaDB or MySQL from CentOS 7 or RHEL 7

I am trying to redirect output of a `systemd` service to a file but it doesn&#39;t seem to work:  

    [Unit]
    Description=customprocess
    After=network.target
    
    [Service]
    Type=forking
    ExecStart=/usr/local/bin/binary1 agent -config-dir /etc/sample.d/server
    StandardOutput=/var/log1.log
    StandardError=/var/log2.log
    Restart=always
    
    [Install]
    WantedBy=multi-user.target

Please correct my approach.

How to redirect output of systemd service to a file

As mentioned above, I need to install only the mongo shell on a RHEL instance (machine A).
I have a mongodb server on a separate instance (machine B) and need to connect to that from A to run `mongodump` and `mongorestore` commands.

I tried looking it up on the web but all I got was instructions to install the complete mongodb package.

Any help appreciated.

Install ONLY mongo shell, not mongodb

I am trying to install `Docker CE` on `RHEL` using this [link][1]. This is my RHEL version:

    Red Hat Enterprise Linux Server release 7.3 (Maipo)

When I execute this:

    sudo yum -y install docker-ce

I am getting this error:

    Error: Package: docker-ce-17.06.0.ce-1.el7.centos.x86_64 (docker-ce-stable)
               Requires: container-selinux &gt;= 2.9
     You could try using --skip-broken to work around the problem
     You could try running: rpm -Va --nofiles --nodigest

I tried using `--skip-broken` and `rpm -Va --nofiles --nodigest` but again getting the same error. Please let me know how to resolve this issue and install Docker CE in RHEL 7.3.

  [1]: https://stackoverflow.com/questions/42981114/install-docker-ce-17-03-on-rhel7


Content Type	Original Author	Original Content on Stackoverflow
Question	Kishore	View Question on Stackoverflow
Solution 1 - Linux	scai	View Answer on Stackoverflow
Solution 2 - Linux	rsm	View Answer on Stackoverflow

Hourly rotation of files using logrotate?

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How to make a ActionBar like Google Play that fades in when scrolling

Optimize GROUP BY query to retrieve latest row per user

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