gen_dotfiles_bazelrc.sh

#!/bin/bash
#
# Generates initial `~/.bazelrc` (for use in any Bazel project (e.g. Drake,
# Anzu, etc.)

set -euo pipefail

dotfile=~/.bazelrc
dotfile_user=
echo "Check if ${dotfile} exists."
if [[ -f ${dotfile} ]]; then
    echo "${dotfile}: already exists! Will not overwrite."
    dotfile_user=${dotfile}
    dotfile=$(mktemp)
    echo "Instead, writing to: ${dotfile}"
fi

echo "Write ${dotfile}"

cat > ${dotfile} <<EOF
# .bazelrc options. For more information, please see:
# https://docs.bazel.build/versions/master/guide.html#bazelrc
# https://docs.bazel.build/versions/master/user-manual.html

build -j HOST_CPUS*0.5

# N.B. Do not use 'common' for these flags since it will break commands like
# 'bazel version'.
fetch --repository_cache ${HOME}/.cache/bazel-externals
fetch --disk_cache ${HOME}/.cache/bazel_local_disk
build --repository_cache ${HOME}/.cache/bazel-externals
build --disk_cache ${HOME}/.cache/bazel_local_disk

# Uncomment these if you wish.

# build --progress_report_interval=5
# Have GCC show color output. May invalidate prior builds.
# build --cxxopt -fdiagnostics-color
EOF

if [[ -n ${dotfile_user} ]]; then
    echo "Show diff"
    echo
    # N.B. Use readlink so that text comparison is performed.
    # N.B. Ignore exit code.
    git --no-pager diff --no-index \
        $(readlink -f ${dotfile_user}) ${dotfile} || :
    echo
    echo "Merge changes using:"
    echo "   $(git config diff.tool) ${dotfile} ${dotfile_user}"
fi