All Questions(ubuntu)

I've tried the normal way, sudo apt-get install python3.6, but... well... that didn't work.

So, how would I go about it? (I'd preferably not build it on my own)

I'm using Ubuntu 16.04.

I am running Ubuntu on an ARM based embedded system that lacks a battery backed RTC. The wake-up time is somewhere during 1970. Thus, I use the NTP service to update the time to the current time.

I added the following line to /etc/rc.local file:

sudo ntpdate -s time.nist.gov

However, after startup, it still takes a couple of minutes until the time is updated, during which period I cannot work effectively with tar and make.

How can I force a clock update at any given time?

UPDATE 1: The following (thanks to Eric and Stephan) works fine from command line, but fails to update the clock when put in /etc/rc.local:

$ date ; sudo service ntp stop ; sudo ntpdate -s time.nist.gov ; sudo service ntp start ; date
Thu Jan  1 00:00:58 UTC 1970
 * Stopping NTP server ntpd     [ OK ] 
 * Starting NTP server          [ OK ] 
Thu Feb 14 18:52:21 UTC 2013

What am I doing wrong?

UPDATE 2: I tried following the few suggestions that came in response to the 1st update, but nothing seems to actually do the job as required. Here's what I tried:

1. Replace the server to us.pool.ntp.org
2. Use explicit paths to the programs
3. Remove the ntp service altogether and leave just sudo ntpdate ... in rc.local
4. Remove the sudo from the above command in rc.local

Using the above, the machine still starts at 1970. However, when doing this from command line once logged in (via ssh), the clock gets updated as soon as I invoke ntpdate.

Last thing I did was to remove that from rc.local and place a call to ntpdate in my .bashrc file. This does update the clock as expected, and I get the true current time once the command prompt is available.

However, this means that if the machine is turned on and no user is logged in, then the time never gets updates. I can, of course, reinstall the ntp service so at least the clock is updated within a few minutes from startup, but then we're back at square 1.

So, is there a reason why placing the ntpdate command in rc.local does not perform the required task, while doing so in .bashrc works fine?

I need a step-by-step, simple and easy way to configure swappiness.

I am lazy at home and use password authentication for my home machines. I am ready to move to key based authentication. There are many options on the web on how to do this, including catting then sshing the key over, scping the key over directly, etc.

I am looking for the easiest and recommended way to copy a key over, hopefully there is a convenience wrapper somewhere in the Ubuntu ssh package?

I'm already aware on how to shut off password logins.

When I open a RAM-intensive app (VirtualBox set at 2GB of RAM), some swap space is generally used, depending on what else I have open at the time.

However, when I quit that last application, the 2GB of RAM is freed up, but the same swap space use remains.

For example, right now, about two hours after having closed VirtualBox, I have 1.6GB free RAM and still 770MB in swap.

How can I tell Ubuntu to stop using that swap and to revert to using the RAM?