vim

• toggle control characters on/off:

:set list
:set nolist

yq

• Render (explode) yaml file using anchors

yq 'explode(.)' < inputfile.yaml

• Select a value from a file containing multiple yaml documents

vault

• assign policy foo to github team admins:

vault write auth/github/map/teams/admins value=foo

• assign policy foo directly to a user in the configured organisation:

vault write auth/github/map/users/glitchcrab value=foo

terraform

importing cloudflare records

• get record ID from Cloudflare API:

curl https://api.cloudflare.com/client/v4/zones/<zone_id>/dns_records?per_page=50&page=1 \
    -H "X-Auth-Key:<api_key>" \
    -H "X-Auth-Email:<account_email>" \

tcpdump

• capture HTTPS ClientHello packets and use tshark to extract Hostnames:

tcpdump "tcp port 443 and (tcp[((tcp[12] & 0xf0) >>2)] = 0x16) && (tcp[((tcp[12] & 0xf0) >>2)+5] = 0x01)" -w output.pcap

tshark -r output.pcap  -Tfields -e tls.handshake.extensions_server_name -Y 'tls.handshake.extension.type == 0' | sort | uniq

tail

• remove the first line of a file:

tail -n +2 file.txt

• tail a file through rotations:

tail -F file.name

ssh

• force SSH to only use password auth

ssh -o PasswordAuthentication=yes -o PreferredAuthentications=keyboard-interactive,password -o PubkeyAuthentication=no

sops

• export private key to decrypt file:

export SOPS_AGE_KEY=AGE-SECRET-KEY-1XJNR6UEP552AMGPVEJZ55849UUK20MKZSDF4SA2XEVJQK2LACXDQFASKE6

• export public key to encrypt file:

sed

• insert a line at the start of a file:

sed -i '1s/^/your text\n/' file

• replace newline char:

sed ':a;N;$!ba;s/\n/NEWCHAR/g' filename

rsync

• rsync saving ACLs and xattrs:

rsync -avPAX

• rsync only files less than $x days old preserving directory path on remote host:

find . -type f -mtime -4 -print0 | rsync -0adv --files-from=- ./ root@target-host:/target/path/