Virtual machine: Preconfigured LAMP stack with php 7

1. Install virtualbox: https://www.virtualbox.org/

2. Download the first VM build which works with virtualbox: https://www.turnkeylinux.org/lampstack

3. Import it into virtualbox. This gives us a LAMP stack with php 5.0

4. Install php7 in the VM: https://shiji.info/blog/2016/en/99

5. disable php5:  a2dismod php5

6. enable php7: a2enmod php7.0

7. restart web server

Exlamaction mark next to wifi icon on android

It indicates the phone cannot connect google servers. A reboot usually solves this if the problem persists.

How to search for images by color

Sometimes when you search for an image you want to see only matches of specific color. Here's a trick to do it with Google Image Search. Search for an image then add this to the link to search, for example, green images:

&imgcolor=green

RSS feed URL for Youtube channels

So Youtube doesn't provide this anymore on the web interface, but this seems to work:

https://gdata.youtube.com/feeds/api/users/channelname/uploads?v=2&alt=rss

Just replace channelname with the name of the channel you want to subscribe to via RSS.

How to unstick the stuck Control key on Windows

Sometimes on my Windows 7 out of the blue the control key becomes stuck, that is the computer behaves like the control key was pressed all the time. It is really annoying, but there is a simple trick to cure it. Just press the control, alt and shift keys on the left side of keyboard, one after the other, then press these keys on the right side one after the other. This usually solves the problem for me.

How to clear the DNS cache of Opera

I didn't find an easy way to do it, but restarting the browser seems to do the trick.

Deleting Gmail messages from Trash when there is no Delete Forever button

If you want to delete a message from GMail Trash to make space in your inbox then you can select the message and press the Delete Forever button. But what if there is no such button, only regular Delete which does nothing in this case, because it just moves the message to the Trash?

It can happen when you want to purge message selectively from Trash, that is you use a search first. (I needed this, because for some reason Gmail did not delete messages older than 30 days, therefore my inbox was almost fulI, so I had to find a way to purge some messages manually from Trash.) If you use search there will be no Delete Forever button. So what can you do?

The solution is searching for the opposite of you want, then label those messages with a new label, move them to the inbox, so only messages you want to delete stay in the Trash. This way you can select them all there and there will be a Delete Forever button, because you do not have to search first to find these messages. Finally, go to the label you chose and delete those messages again, so they go back to the Trash.

Here's an example: say, you want to delete messages from Trash which have an attachment, but you want to leave other messages in the trash, because you might need them later.

You can search for them like this:

in:trash has:attachment

But according to the above you want the opposite, those messages which do not have an attachment (note the - character):

 in:trash  -has:attachment

Run this search and mark all of these messages with a new label (say "trashtemp"). Then after labelling them, move them into the Inbox. Then go back to Trash, select all of the remaining messages and delete them forever. Finally, go to the trashtemp label, select all messages under it and delete them to make them go back to the Trash.