bugfix: lib/sh/db.sh: pg_cmd(): only set PG* connection/login env vars when the corresponding var is non-empty. there are some situations in which these must be unset (in order to use the default value), and other situations when the var must be set to something (i.e. "") to avoid it being defaulted to a value in local.sh > connection vars.

backups/TNRS.backup.md5: updated

bugfix: inputs/.geoscrub/geoscrub_output/geoscrub.csv.run: need to set $local_pg_database instead of $database because use_local (in psql()) does not currently avoid clobbering already-set versions of the applicable env vars

bugfix: lib/sh/local.sh: pg_as_root(): need to use -E (preserve environment) option to sudo, so that $schema, $table get passed through

bugfix: lib/sh/local.sh: psql(): only \set schema, table if $schema, $table are non-empty, because otherwise, you will get a "zero-length delimited identifier" error

added inputs/.geoscrub/geoscrub_output/geoscrub.csv.run to export the geoscrub table (must be run on vegbiendev)

lib/sh/local.sh: added require_remote()

lib/sh/db.sh: added pg_as_root()

lib/runscripts/util.run: added $wrap_fn to run any function via sudo, etc.

Added instructions for dependencies in the README.