Cheatsheet

• Bash
  • https://www.shellcheck.net/
  • https://google.github.io/styleguide/shellguide.html
  • https://mywiki.wooledge.org/BashPitfalls
• CEL
  • Language Definition
  • https://celbyexample.com/
• DNS
  • https://dnsviz.net/
• Fossil
  • Reference a ticket in commit message with [123456]
  • Show changed files fossil diff --brief
  • Show diff in browser fossil diff --by --context 15
  • Show untracked files fossil extras --dotfiles
  • Create new repo fossil init repo.fossil --admin-user admin (see terminal output for password)
  • Testing with self-signed certs fossil set --global ssl-ca-location ca.crt
• htpasswd
  • ./htpasswd -b -B bcrypt htpasswd user password (-c to create the file, -n instead of -b to print to stdout)
  • https://httpd.apache.org/docs/current/programs/htpasswd.html
• HTTP
  • https://www.iana.org/assignments/http-fields/http-fields.xhtml
• Incus
  • Setup PKI using KeyStore Explorer
    • Generate key pairs in a temporary key store for CA, server and client (Add extensions > Use Standard Templates > CA, TLS/SSL Server and TLS/SSL Client respectively)
    • Create CSRs for server and client
    • Sign CSRs with CA (Transfer Extensions, Export Length: Entire Chain)
    • Create password protected client keystore (containing client private key and signed cert) and truststore (containing ca cert) in PKCS#12 format
    • Place server key and signed cert in /var/lib/incus
    • Restart incus service
    • Trust signed client cert incus config trust add-certificate client.crt
  • IPv6 connectivity with static prefix, eg. 1234:1234:1234::/48
    • incus network set incusbr0 ipv6.address=1234:1234:1234:cccc:1:1:1:1/64 ipv6.nat=false
    • pfSense
      • System / Routing
        • Gateways > Add
          • Set gateway IP address to IP of Incus host
        • Static Routes > Add
          • Destination 1234:1234:1234:cccc:1:1:1:1/64
    • https://blog.sifrmoja.xyz/posts/public-ipv6-lxd/
  • CLI
    • Use --debug to to see API calls (also --verbose)
  • Login as user incus exec my-instance -- su --login ubuntu
  • Images
• Java
  • List all system properties java -XshowSettings:properties -version
  • Debug security/certificates -Djava.security.debug=all
• JSON
  • https://json-everything.net/
• Linux
  • Network ip address show
  • File system df --block-size=M
  • OS/distro /etc/os-release
  • APT versions apt policy wireguard (also apt-cache madison wireguard)
  • User list getent passwd
  • Group list getent group
  • User in group getent group | grep user
  • First 75 lines cat -n <( head -75 step_queue.json )
• Maven
  • mvn buildplan:list
  • mvn help:effective-pom -Dverbose
  • List dependencies mvn dependency:tree -Dverbose
  • Update dependencies mvn versions:display-dependency-updates "-Dmaven.version.ignore=.*alpha.*,.*beta.*,.*-M.*,.*-proto.*"
  • Update plugins mvn versions:display-plugin-updates -N "-Dmaven.version.ignore=.*alpha.*,.*beta.*,.*-M.*,.*-proto.*"
  • Testing with self-signed certs, in .mvn/jvm.config set -Dmaven.resolver.transport=wagon -Dmaven.wagon.http.ssl.insecure=true
  • Lifecycle
  • Condition-Based Profile Activation
• Misc
  • https://excalidraw.com/
  • https://gchq.github.io/CyberChef/
• NPM
  • Run ESLint fix mvn exec:exec@es-eslint-fix
  • List dependencies npm ls --all (also --omit dev)
  • Update dependencies npm outdated
  • Testing with self-signed certs, in .npmrc set strict-ssl=false
• Promontory
  • Installer
    • Requirements
      • Sudo sudo -i
      • Unzip apt-get install --quiet --yes unzip
    • Move installer.zip to /var/tmp
    • Unpack and prepare cd /var/tmp && unzip -qq installer.zip -d installer && cd installer && chmod +x install.sh
    • Install ./install.sh my_runbook
• Regex
  • https://regex101.com/
• SQLite
  • Date/Time
  • Datatypes
  • PRAGMA
  • WAL
• SSH
  • Create user just for ssh login adduser --comment "user" --disabled-password --quiet user
  • Unlock user usermod --password '*' user
• systemd
  • Show unit log journalctl --no-pager --lines 100 --unit myunit
  • Follow unit log journalctl --follow --unit myunit (or -fu)
  • Show unit with drop-ins systemctl cat myunit
• Wireguard
  • https://wiki.archlinux.org/title/WireGuard#Key_generation