Linux Troubleshooting & Random LifeHax

Lifehack

I don’t use which, I rely type or even type -a to list all possible interpretations.

BASHRC

Powerline10k

if [ -f /usr/share/powerline/bindings/bash/powerline.sh ]; then
  powerline-daemon -q
  POWERLINE_BASH_CONTINUATION=1
  POWERLINE_BASH_SELECT=1
  source /usr/share/powerline/bindings/bash/powerline.sh
fi

1Password SSH integration

export PATH="/home/daniel/.local/bin:$PATH"
SSH_AUTH_SOCK=~/.1password/agent.sock

PROFILE

Start ssh-agent with env vars:
eval ssh-agent

Launch script at startup or reboot

Place absolute path to /etc/rc.local
or add @reboot with your script path intro /etc/crontab

Troubleshooting

Warning: unable to delete old directory

This can happen if we have residual files that were not deleted for some reason. Though sometimes responsible packages are present, meaning we have leftover from previous versions or some manually placed configurations, which aren’t tracked by dpkg:

dpkg: warning: unable to delete old directory '/lib/systemd/system-generators': Directory not empty dpkg: warning: unable to delete old directory '/lib/systemd/system/[email protected]': Directory not empty

To check which installed packages are responsible for the files in path:

sudo dpkg -S /lib/systemd/system-generators/*
sudo dpkg -S /lib/systemd/system/[email protected]/*

In my case all of files were unrelated to installed packages

To check which repo (online) packages are associated with files in path:

sudo apt install apt-file
sudo apt-file update
apt-file search /lib/systemd/system-generators
apt-file search /lib/systemd/system/[email protected]

We found repo packages responsible for all the files, we should cross reference this output with folder contents.

So far we figured that packages seem to be not installed, but their files remain, strange! Let’s actually check if we have these packages:
dpkg-query --no-pager -l '*systemd*' '*cloud-init*' '*netplan*' '*snapd*' '*openssh*'

Please note that in my original output netplan and cloud-init were actually installed, lost that screenshot

From all these package we don’t need, there is netplan and cloud-init, these are unrelated to WSL, let’s remove them:

sudo apt-get purge cloud-init netplan-generator netplan.io python3-netplan
sudo apt-get update
sudo apt-get install -f
sudo apt-get autoremove
sudo apt-get autoclean

File system

CIFS: Unable to determine destination address
Just install cifs-utils

Make VM unique (CentOS/RHEL)

rm /etc/machine-id
# also remove any monitoring software packages and folders

• Remove existing machine ID

sudo rm /etc/machine-id
sudo rm /var/lib/dbus/machine-id
sudo init 6

• Regenerate machine ID

sudo dbus-uuidgen --ensure
sudo systemd-machine-id-setup

• Verify machine ID

cat /etc/machine-id
hostnamectl

Key is stored in legacy trusted.gpg keyring

Example of the output:

13 packages can be upgraded. Run 'apt list --upgradable' to see them.
W: https://aquasecurity.github.io/trivy-repo/deb/dists/noble/InRelease: Key is stored in legacy trusted.gpg keyring (/etc/apt/trusted.gpg), see the DEPRECATION section in apt-key(8) for details.
➜  ~ sudo apt-key list
Warning: apt-key is deprecated. Manage keyring files in trusted.gpg.d instead (see apt-key(8)).
/etc/apt/trusted.gpg
--------------------
pub   rsa3072 2019-05-06 [SC] [expires: 2029-05-03]
      2E2D 3567 4616 32C8 4BB6  CD6F E9D0 A361 6276 FA6C
uid           [ unknown] trivy
 
/etc/apt/trusted.gpg.d/ubuntu-keyring-2012-cdimage.gpg

Solution:
sudo apt-key list
sudo apt-key export 6276FA6C | sudo gpg --dearmour -o /etc/apt/trusted.gpg.d/trivy.gpg