Problem
You are trying to upgrade one of your gems (ie uglifier) and at the same time you are using a new gemset (ie for rails 4.2.4), and you get the following error when you are trying to bundle:
Could not find libv8-3.16.14.9 in any of the sources
Solution
Upgrade to rails 4.2.4 first and bundle and afterwards change the other gem and do bundle again.
If you would like to know how your linux system was booted type the following to give you the information that you need:
$ cat /proc/cmdline BOOT_IMAGE=/boot/vmlinuz-3.13.0-62-generic.efi.signed root=UUID=7ef51656-acfc-4d01-aa94-90f7042b2e28 ro quiet splash vt.handoff=7
Problem
You have multiple pdf pages and you want to combine them into one file.
Solution
Use pdftk to combine them into one file like:
pdftk page1.pdf page2.pdf page3.pdf cat output combined_file.pdf
Problem
You have started a couple of guest linux sessions on your pc, that you do not need anymore (ie giving access to your children while on holiday 🙂 ), and you want to close them from your own session.
Solution
Find out about the guest users by using who:
who ... guest-kk9tnS :2 2015-08-09 17:39 (:2) guest-kk9tnS pts/21 2015-08-09 17:40 (:2)
and then kill the sessions using pkill:
sudo pkill -9 -u guest-kk9tnS