PerlDuck's questions

Recently I created an encrypted filesystem (crypto_LUKS) that serves as $HOME for just one particular user (i.e. I mount it as /home/pduck). I also added an appropriate entry in /etc/security/pam_mount.conf.xml so that the partition gets automatically decrypted and mounted when the user logs in (and unmounted when he logs off). Works great.

Because the $HOME is a filesystem on its own, the user has a lost+found directory owned by root:root in it. I know that deleting the directory is a bad idea but many commands (e.g. find) complain about having no access. That annoys me.

Out of curiosity I removed the directory and recreated it with mklost+found (without sudo). Now the directory is owned by pduck:pduck. Is that ok or is it crucial that the directory is owned by root:root?

The question Best practice when mounting a new disk within an existing mount? inspired me to ask this follow-up question:

The other question asked whether it is ok to

mount /dev/sdb1 /home
mount /dev/sdb2 /home/mythtv

so that /home/mythtv is a mountpoint within the mountpoint /home. (spoiler: Yes, it is perfectly ok.).

What if I'd change the order of commands to

mount /dev/sdb2 /home/mythtv
mount /dev/sdb1 /home

Will that yield the same result or will /home/mythtv be hidden by /home? I assume /home contains an (empty) directory /home/mythtv.

I'm currently on 17.10 and don't use encryption on my internal drives but have an external USB disk which is encrypted. I use it for backups.

Because I am was not sure whether I use ecryptfs or cryptsetup I show the steps it took to set up the external disk:

1. Activities → Disks → Select drive → Create Partition → Format Volume:

   

2. Enter Password (twice) → Create

   

When I plug in the HDD, Ubuntu prompts me to enter the passphrase and then mounts it. It works like a charm and I'm able to write my backups to that external disk. There are no .Private folders and no other files besides the one I put there (plus the lost+found folder). For illustration I used a 4GB stick here but the steps were the same with the actual disk.

From some comments I learned this happens to be cryptsetup then and not ecryptfs.

What will happen when I upgrade to 18.04? Given 18.04 doesn't support encryption by default, I'm afraid I cannot restore my backups any longer.

Will it make a difference when I don't upgrade but do a fresh install?

Recently my computer turned on unexpectedly. It is configured to respond to WOL (Wake-On-LAN) but at that time I didn't send any magic packet. It came on out of nowhere.

How can I figure out why it turned on? I already looked at journalctl -b and grepped through various logfiles below /var/log but couldn't find any hint.

Up to 17.04 the behaviour was:

When I plug-in an external drive (USB stick, HDD), then it showed up in the sidebar. This was convenient because I was able to eject/safely remove/open it by using the icon in the sidebar.

Now (17.10) an external drive creates an icon on the desktop at some free random place when plugged in. In order to access the icon to eject/safely remove/open the drive, I need to either minimize all windows or switch to another (empty) workspace.

How can I make these external drive icons appearing in the sidebar instead?

When I lock my screen with Windows+L the lockscreen's background image is shown for just about a second or so (presumably less) and then the screen turns off.

Is there a way to keep the lockscreen image for a while, say 5 minutes or so before the screen turns black?

I mean, what's the purpose of configuring an image when only flies or hummingbirds can actually recognize it?

I'm on U17.10 with Wayland.

I use a coloured bash prompt like so:

blue=$(tput setaf 4)
reset=$(tput sgr0)
bold=$(tput bold)
export PS1='($?) \[$bold$blue\]\u@\h:\w\[$reset\]$(__git_ps1)> '

I usually work in a terminal window (gnome-terminal) but sometimes in a full-screen console (CTRL+ALT+F3).

My coloured prompt is fine in the GUI terminal but hard to read in full-screen because the colours look different. So I'd like to use a different colour (e.g. cyan=$(tput setaf 6)), when in console window. For this to work I need to figure out which mode I'm currently in and set my $PS1 accordingly.

I tried the tty command. It gives

/dev/pts/0  # GUI terminal
/dev/tty3   # console 

I also tried to examine the value of $TERM. It gives

xterm-256color  # GUI terminal
linux           # console

Both of them would work for me but my question is: Is that the correct way to reliably distinguish console vs. terminal or are there better ways? I'm on 17.10.1 if that matters.