I have been working on a proof of concept using CouchDB. After getting the proof of concept working, I spun up a digital ocean droplet and proceeded to setup CouchDB on the server. I went to enable the SSH tunnel so I could access the CouchDB Futon instance and promptly ran into an error because my local instance of CouchDB was using the same port, 5984. I had a lot of trouble finding out an easy way to stop CouchDB because the documentation in the Wiki wasn’t accurate:
1 2 | sudo launchctl unload \ /usr/local/Library/LaunchDaemons/org.apache.couchdb.plist |
As a workaround, in Terminal, run
1 | launchctl list | grep couchdb |
This will output something like:
99093 0 org.apache.couchdb.288008
Grab the highlighted portion and run
1 | launchctl stop "org.apache.couchdb.288008" |
Substitute the process name accordingly and you should be able to run the ‘launchctl list’ command again and see the process is no longer present.
I 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.
1 | 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:
1 | sudo service nginx stop |
Now you should be able to start apache.
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 |
Paste this snippet into the textbox in the console window:
1 | <del datetime="2016-09-21T17:09:17+00:00">!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()}();</del> |
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 !@#$%^&*()_+
1 | !function(){function t(){function n(t,e){s=s.concat(RFB.messages.keyEvent(t,e))}var o=e.shift(),s=[],i=o.charCodeAt(),c=-1!=='!@#$%^&*()_+{}:"<>?~|'.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.
Greg