====== Scraps ======

Bits and pieces I want to be able to grab quickly. This page will change frequently.

===== Disable power button shutdown =====

edit /etc/systemd/logind.conf

uncomment HandPowerKey, set to ignore

===== Get & Set date w/ epoch time =====

Get from good machine:

<code>date +%s</code>


Set on another:
<code>date -s '@1705865491'</code>
===== Image and Compress Disk =====
<code>
dd if=/dev/sda bs=100M | pv -ptera -s500G | lz4 > backup-name.dd.lz4
</code>
(-s500G refers to the image size, for estimates)

Mount the whole disk image: (have to un-lz4 first ofc)

<code>
kpartx -a -v myimage.disk

mount /dev/mapper/loop0p1 /mnt/myimage
</code>

Then, to unmount:

<code>
umount /mnt/myimage

kpartx -d -v myimage.disk
</code>
===== ntplogtemp =====

<code>
#!/bin/bash
/usr/local/bin/ntplogtemp -o -l /chronyLogs/temps
sed '/ZONE0/d' -i /chronyLogs/temps
sed '/sensor/d' -i /chronyLogs/temps
sed -i 's/LM0/CPU/g' /chronyLogs/temps
sed -i 's/LM1/CPU/g' /chronyLogs/temps

</code>

===== cycle systemd logs =====
<code>sudo journalctl --rotate ; sudo journalctl --vacuum-time=1s</code>

==== show systemd logs from boot ====
<code>sudo journalctl -b</code>

===== Raspberry Pi =====
==== Quick Pi ID ====

Easy way to get a quick visual indicator to ID a Pi you're remoted into:

Blink pwr LED at 1Hz:

<code>
echo timer | sudo tee /sys/class/leds/led1/trigger

</code>

Set pwr LED back to monitor voltage:
<code>

echo input | sudo tee /sys/class/leds/led1/trigger

</code>

==== Heartbeat LED ===
set in config.txt

<code configtxt>
dtparam=act_led_trigger=heartbeat

</code>

==== Grow partition on first boot ====
Add to the end of /boot/cmdline.txt

<code>
quiet init=/usr/lib/raspi-config/init_resize.sh
</code>
===== chronyc tracking =====

-m flag combines commands. For example: sources -v, tracking, sourcestats -v
<code>

chronyc -m 'sources -v' tracking 'sourcestats -v'

</code>

===== DHCP and Static IP on the same interface =====

Ubuntu Server 20.04, should apply to netplan in general.

<code>
network:
  version: 2
  ethernets:
    eno1:
      dhcp4: true
      addresses:
        - 172.16.1.20/22
      gateway4: 172.16.0.1
      nameservers:
        search:
          - syninf.net
        addresses:
          - 172.16.0.2

</code>

===== Find files under certain size and move them =====

<code>
find . -type f -size -150M -exec mv {} ../junk \;

</code>

===== nmap testers =====

NTP

<code>
sudo nmap -sU -p 123 --script ntp-info 172.16.1.6

</code>

DHCP

<code>
sudo nmap -sU -p 67 --script=dhcp-discover 172.16.0.2

</code>

===== Standalone certbot DNS =====

<code>
sudo certbot certonly --manual --preferred-challenges dns -d webgis.syninf.net

</code>

===== rsync incremental copy =====

[[https://www.redhat.com/sysadmin/sync-rsync|https://www.redhat.com/sysadmin/sync-rsync]]
<code>

sudo rsync -avuP /mnt/data/media/ /mnt/six/media/

</code>

===== Add NTP Server to PiHole DHCP =====

<code>
echo 'dhcp-option=42,172.16.0.2' | sudo tee /etc/dnsmasq.d/42-pihole-dhcp-ntp.conf

</code>

Restart pihole
<code>

sudo service pihole-FTL reload

</code>

===== Build LinuxPTP on Alpine =====
Enable community repository 

install deps
<code>apk add alpine-sdk linux-headers bsd-compat-headers </code>

<code>git clone git://git.code.sf.net/p/linuxptp/code linuxptp</code>

<code>make ; make install</code>

===== Cycle Chrony Logs =====
<code>
#!/bin/bash
# chrony log rotation

cd /var/log/chrony

mv measurements.log measurements.$(date +"%Y%m%d").log
mv statistics.log statistics.$(date +"%Y%m%d").log
mv tracking.log tracking.$(date +"%Y%m%d").log

sync

chronyc cyclelogs
</code>

===== chrony.conf ptp as pps refclock =====
<code>
server time-a.nist.gov
server time-a-wwv.nist.gov

refclock SHM 0 poll 3 refid GPS
refclock PHC /dev/ptp0:extpps:nocrossts:pin=0 width 0.1 refid PHC pps

logdir /var/log/chrony
log statistics tracking measurements

driftfile /var/lib/chrony/chrony.drift

dumpdir /etc/chrony/dump

rtcsync

allow
cmdallow
</code>

===== Proxmox =====
==== re-number VM ====

1) shut down VM
2) rename the storage
<code>zfs rename pool1/vms/vm-112-disk-0 pool1/vms/vm-1001-disk-0</code>
3) rename the configuration file
<code>
export vgNAME=vg-images newVMID=173 oldVMID=175 ;  \
sed -i "s/$oldVMID/$newVMID/g" /etc/pve/qemu-server/$oldVMID.conf; mv /etc/pve/qemu-server/$oldVMID.conf /etc/pve/qemu-server/$newVMID.conf; \
unset vgNAME newVMID oldVMID;
</code>