Unable to rename in go projects in vscode

vscode used to use gorename to do the renames. However, gorename does not support go modules. gopls should be used instead. If it is not available to your project, try to add the following in your configuration file:

"go.languageServerExperimentalFeatures": {
    "rename": true
}

Run command on suspend

Create a file located in /usr/lib/systemd/system-sleep directory:

#!/bin/sh
if [ "${1}" == "pre" ]; then
  nordvpn d
elif [ "${1}" == "post" ]; then
  echo "Hello"
fi

Debug route table

List all routes in system:

route -n

Get route for a specific IP:

ip route get 1.1.1.1

Log denied connections in firewalld

Edit filr /etc/sysconfig/firewalld:

FIREWALLD_ARGS=--debug=10

Wait until able to connect

while ! nc -w5 -z 10.0.0.100 22; do echo "hello"; done

Log executed command

14:27 $ (set -x; sleep 1 && sleep 2)
+ sleep 1
+ sleep 2

Check and modify connection mtu

To check:

[root@lxd-node3 ~]# netstat -i
Kernel Interface table
Iface             MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
ens10            1450      455      0      0 0           671      0      0      0 BMRU
eth0             1500       28      0      0 0            32      0      0      0 BMRU
lo              65536        0      0      0 0             0      0      0      0 LRU

Modify temporarily:

ifconfig eth0 mtu 1450

Permanently: edit /etc/sysconfig/network-scripts/ifcfg-eth0 file and add:

MTU=1450

lxd: Fix version in snap

 snap refresh lxd --channel=3.18

fedora: Lockdown a kernel version

Fedora typically keeps 3 latest kernel versions. However, what if you want to keep an old specific kernel version which is known to work well with your system? First, we need to install a dnf plugin that allows us to keep a specific version of any package:

sudo dnf install python3-dnf-plugins-extras-versionlock

Lets find all available kernel versions for your system:

sudo dnf list kernel --showduplicates

Install that specific version of the kernel:

sudo dnf install kernel-5.3.7-301.fc31

And lock it:

sudo dnf versionlock add kernel-5.3.7-301.fc31

To remove the lock:

sudo dnf versionlock delete kernel-5.3.7-301.fc31

Dell Precision 5540 - Battery drains in sleep mode

Run the following command to check the suspend mode:

cat /sys/power/mem_sleep 

If the output looks like this:

[s2idle] deep

It means that very inefficient suspend mode is active (drains battery from 100% to 0 in 9 hours). To enable "deep" mode, edit file /etc/default/grub and append "mem_sleep_default=deep" to GRUB_CMDLINE_LINUX:

GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="rd.lvm.lv=fedora/root rd.lvm.lv=fedora/swap rhgb quiet mem_sleep_default=deep"
GRUB_DISABLE_RECOVERY="true"
GRUB_ENABLE_BLSCFG=true

Apply changes:

sudo grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg

Restart your laptop and verify changes:

$ cat /sys/power/mem_sleep 
s2idle [deep]

Increase storage of a lxd container

By default lxd stopped to assign root (disk) device to a container. To modify storage volume of a container add a device like this:

lxc config device add surflyc root disk pool=default path=/ size=15GB

Restart the container to apply changes.

Log quireis in dnsmasq

Add the following line to dnsmasq configuration file: log-queries

Lxd on Fedora 31

Fedora 31 has started to use cgroups v2 by default. According to Common F31 bugs it doesn't play nice with Docker, lxd and others. To make fedora switch back to the old cgroups:

sudo grubby --update-kernel=ALL --args="systemd.unified_cgroup_hierarchy=0"

How to regenerate grub configuration

sudo grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg

wifi utils

List used wifi frequences

sudo iwlist wlp1s0 scan | grep Frequency | sort | uniq -c | sort -n

List available channels

iwlist channel

List wifi networks

nmcli d wifi