anchor.diff:  #-----------------------------------------------------------------------------#
   # Install PETSc to system path
   #-----------------------------------------------------------------------------#
  -ARG PETSC_REV
  +ARG PETSC_REV=a7279e6a5f0ea1f621d894c55a771197241f8708
   ARG PETSC_OPTIONS
   ENV PETSC_DIR=/usr/local
   COPY scripts/update_and_rebuild_petsc.sh ${MOOSE_DIR}/scripts/update_and_rebuild_petsc.sh
  
positive.code: #-----------------------------------------------------------------------------#
  # Install Libmesh to system path
  #-----------------------------------------------------------------------------#
  ARG LIBMESH_REV
  ARG LIBMESH_OPTIONS
  ARG LIBMESH_METHODS="opt dbg"
  ENV LIBMESH_DIR=/usr/local \
  
negative.code: # involve MOOSE, leading to unneccessary, redundant use of computing
  # resources, bandwidth, and storage.
  #
  # Optional arguments (set with --build-arg):
  # DISTRO_NAME: Linux distribution; defults to ubuntu.
  # DISTRO_VERSION: Linux distribution version; defaults to 20.04 with ubuntu.
  # LIBMESH_METHODS: Methods with which to build libmesh; defaults to "opt dbg".
  # MOOSE_JOBS: Sets number of cores for running make; defaults to 1.
  # MOOSE_METHODS: Methods with which to build MOOSE; defaults to opt.
  # PETSC_REV: Commit hash of submodule petsc.
  # PETSC_OPTIONS: Options to pass to update_and_rebuild_petsc.sh.
  # LIBMESH_REV: Commit hash of submodule libmesh.
  # LIBMESH_OPTIONS: Options to pass to update_and_rebuild_libmesh.sh.
  # BUILD_MODULES: Set to build all MOOSE modules.
  #-----------------------------------------------------------------------------#
  ARG DISTRO_NAME=ubuntu
  ARG DISTRO_VERSION=20.04
  