How to Prevent Raspberry Pi Zero from Blanking or Sleeping
I was setting up a Raspberry Pi Zero in an office to use for displaying a slide show of pictures on a TV in the waiting room and dismayed to learn it would constantly go to sleep after a few minutes. I researched and tried setting the consoleblank=0 in config.txt with no luck along many other solutions, but learned none of them worked for the Raspberry Pi Zero.
sudo apt-get update && sudo apt-get install xscreensaverI’m not sure why, but I got an error that some dependencies were not installed. If that happens to you as well, run this command in terminal:
sudo apt-get --fix-missingand then run the install for xscreensaver again
sudo apt-get install xscreensaverNow under Preferences, you’ll see a new option for screen saver:
On the Display Modes tab, you’ll see a drop down for Mode. Choose “Disable Screen Saver”:
Your raspberry pi zero will now no longer go to sleep.
One-line snippet to update linux and apps on Ubuntu using apt-get
I find myself using this command on Digitalocean droplets fairly often and am sharing in case anyone else finds it useful. Use this one line to install all updates, security fixes, and system upgrades.
sudo apt-get update && sudo apt-get upgrade && sudo apt-get dist-upgrade
Cheap Macbook Pro Docking Solution for about $30
I typically prefer developing on my desktop and large dual screen monitor setup as opposed to my Macbook. Recently, I’ve gotten into more PHP development and developing on the Mac is proving to be a more enjoyable experience only because Windows is still a second class citizen for most PHP libraries/tools. I still wanted a larger screen setup, so I considered buying a docking station to hook up to a larger monitor but I soon learned they feature the ‘Mac Penalty’ in that they cost more than they should just because it’s for Apple products.
I already have two large monitors and figured my Macbook could serve as third screen. Then I did some thinking and realized I could use one of the monitors for both computers. Assuming you have two HDMI screens already hooked up to your desktop, this would save you $150+ and still allow you to be more productive.
- Get a copy of Synergy (http://symless.com/) for $10. It’s open source and can be built if you have the time, but a one time fee of $10 saves me the hassle of doing so. With this, you can share your desktop keyboard across all your computers with the one license and it’s cross platform so Linux support is included too.
- Purchase an auto HDMI switcher. I purchased the PORTTA PET0301S 3×1 Port HDMI Switch/Switcher for about $9.
- Be sure to get 2 HDMI cables if you don’t already have them on hand. I don’t like the Amazon Basic brand for these as I’ve had problems with the Mac and those cables hooking up to larger screens.
- Install Synergy on the desktop as a server. Install on the Macbook as a client and it should autoconnect.
- Plug the HDMI cable from the computer into the HDMI switcher, and plug the spare into the Macbook pro. Plug the “Out” end into the monitor.
When you plug your HDMI cable into the Macbook, the HDMI switcher will automatically switch to it and project the Macbook. Synergy will auto-connect as long as it’s running on both and you can share the mouse and keyboard between both and work seamlessly.
If you have an iPad and want to turn that into an additional screen, grab a copy of Duet Display on your desktop/Macbook and install on your iPad for $15.99, and viola, instant portable second screen!
How to repair permissions on Linux Apache /var/www/html folder
I recently ran into an issue where I could no longer FTP files to my Linux droplet when multiple users were uploading to the server. The server kept the user as the owner despite me adding them to the www-data group. This fix comes from my ex-boss, James Tomasino who was kind enough to provide some help since I was stumped. I’m sharing in case anyone else runs into the same issue and finds it useful.
You’ll need to fire up terminal, ssh to the server, and then execute these commands:
cd /var/www sudo chmod 775 html sudo chgrp www-data html sudo chmod g+s html
+s makes permissions sticky so that all files will inherit from the parent directory. This was the setting I was missing.
Open up /etc/ssh/sshd_config. I use nano so:
sudo nano /etc/ssh/sshd_config
Hit CTRL+W and look for “subsystem” which is typically located near the bottom of the file. Change
subsystem sftp /usr/lib/openssh/sftp-server
to
subsystem sftp /usr/lib/openssh/sftp-server -u 0002
If you already have files in the HTML folder, you’ll want to run these commands to reset the permissions:
cd /var/www/
sudo chgrp -R www-data html
find . -type f -exec chmod 664 {} \;
find . -type d -exec chmod 775 {} \;
(98)Address already in use: AH00072: make_sock: could not bind to address [::]:80 – error
IÂ recently got handed a new Ubuntu droplet at work to setup and work on. I was going through the typical configuration to lock down the server and go to installing Apache when I suddenly ran into the error
(98)Address already in use: AH00072: make_sock: could not bind to address [::]:80 – error
I was a little surprised considering I had only run 4 commands total on a brand new installation. If you’re getting this error like me, you’ll need to find out what’s being bound to port 80 and then stop it. Use this command to get a list of anything that’s running on port 80.
sudo lsof -i:80
For me, it turned out nginx was running and bound to port 80. If you have the same problem, run this command to stop it:
sudo service nginx stop
Now you should be able to start apache.
How to Copy and Paste into the Digital Ocean VNC Console
I recently signed up for Digital Ocean to test droplets for my development and linux management testing. I was securing the server and setup fail2ban, disabled the root login, and created a user account but forgot to change the user name from root to the user name I selected in my SSH client profile. I ended up locking myself out of the server and had to resort to logging into the admin panel on Digital Ocean’s website and use their browser embedded VNC client to restore my access. I quickly discovered that one of the downsides of using this panel is that you can’t copy and paste commands. Luckily there’s a workaround and you can use the browser console to do sendkeys through Javascript.
Bring up the console in the browser developer tools. Here’s a cheat sheet for keyboard shortcuts:
| Browser | Description | Windows | Mac |
|---|---|---|---|
| Chrome | Open Developer Tools and bring focus to the console | Ctrl + Shift + J | Cmd + Opt + J |
| Firefox | Open Console | Ctrl + Shift + K | Cmd + Opt + K |
| Internet Explorer | After hitting F12, you have to click the console tab. There’s no direct shortcut to the console tab. | F12 | N/A |
!function(){function t(){window.rfb.sendKey(e.shift().charCodeAt()),e.length>0&&setTimeout(t,10)}var e=prompt("Enter text to be sent to console").split("");t()}();
Update 9-21-16
Ruden and Sebastiaan’s pointed out there was a bug in the code above. This updated snippet has support for characters when using shift characters like !@#$%^&*()_+
!function(){function t(){function n(t,e){s=s.concat(RFB.messages.keyEvent(t,e))}var o=e.shift(),s=[],i=o.charCodeAt(),c=-1!=='!@#$%^&*()_+{}:"<>?~|'.indexOf(o),r=XK_Shift_L;c&&n(r,1),n(i,1),n(i,0),c&&n(r,0),rfb._sock.send(s),e.length>0&&setTimeout(t,10)}var e=prompt("Enter text to be sent to console").split("");t()}();You’ll receive a dialog prompt to enter the copy to paste in. Please note that you need to click on the VNC console and hit enter to execute the command.
If you need to enter more than one command, just hit the up arrow on your keyboard in the console to get the script again for easy reuse.