Direnv: universal export_alias function

.direnvrc

export_alias() {
  local name=$1
  shift

  local alias_dir="$PWD/.direnv/aliases"
  local alias_file="$alias_dir/$name"
  local oldpath="$PATH"

  mkdir -p "$alias_dir"

  if ! [[ ":$PATH:" == *":$alias_dir:"* ]]; then
    PATH_add "$alias_dir"
  fi

  {
    echo '#!/usr/bin/env bash'
    echo 'set -e'
    echo "PATH=\"$oldpath\""
    echo -n 'exec '
    printf '%q ' "$@"
    echo '"$@"'
  } > "$alias_file"

  chmod +x "$alias_file"
}

.envrc

export_alias alembic-hrev bash -c 'alembic revision --rev-id "$(date +%Y_%m_%d_%H%M)" -m "$*"' _

# Usage: alembic-hrev "initial migration"