postgresql

Upgrading postgres under docker

docker run -it --rm --mount \
  type=bind,source=`pwd`/data-dir,target=/var/lib/postgresql \
  -e POSTGRES_PASSWORD=password \
  -e POSTGRES_USER=paperless \
  -e POSTGRES_DB=paperless \

pacman

• reset filesystem permissions:

sudo LANG=C pacman -Qkk 2>&1| awk '/^warning.* mismatch/ {print $3}'| sudo pacrepairfile --uid --gid --mode

openssl

• testing OpenSSL connections with client certificate auth:

openssl s_client -connect domain.com:443 -cert /path/to/cert.pem -key /path/to/key.key

• viewing SSL certificate returned by remote server:

echo | openssl s_client -connect hosting.simonweald.com:465 2>/dev/null | openssl x509 -text

nmap

• Find a host’s IP by MAC address:

sudo nmap -sP 10.101.0.0/22 | grep -i -B 2 "90:09:d0:15:44:81"

misc

• Allow applications to bind to privileged ports:

  sudo setcap 'cap_net_bind_service=+ep' `which tsh`
  sudo getcap `which tsh`
  sudo setcap 'cap_net_bind_service=-ep' `which tsh`
  

jq

• piping jq to less with colour:

jq -C . data.json |less -R

• piping streaming output to jq:

grep

• grep for $string1 AND $string2:

grep -RiE 'rabbit.*guest' /etc/*

• diff files and show only common lines:

git

Sparse checkouts

Useful when you only need a few files checked out in large repos

git clone -n --depth=1 --filter=tree:0 git@github.com:giantswarm/control-plane-catalog.git
# add the directories you want to work in
git sparse-checkout set --no-cone . oauth2-proxy-3.2.0.tgz-meta/

find

• find .php files modified in the last 3 days:

find * -type f -mtime -3 | grep -i "php" | grep -v -i -E "cache|log|template

docker

Build arm64 image on amd64 host

 docker buildx build --platform linux/arm64 -t glitchcrab/ubuntu-debug:latest --output=type=registry .