Script to setup `~/.pgpass` from `~/.pgpass.copy` or `~postgres/.pgpass`

setup-pgpass.sh

#!/bin/bash
# setup-pgpass
# execute (or source) this script to ensure that ~/.pgpass has the most recent credentials
#
# if ~/.pgpass.copy exists, it is used as a source; otherwise, compare against
# ~postgres/.pgpass, and create ~/.pgpass and ~/.pgpass.copy from
# ~postgres/.pgpass

MY_PGPASS=~/.pgpass
PG_PGPASS=~postgres/.pgpass

pgpass_too_small() {
  (( `wc -l <$MY_PGPASS` <= 1 ))
}

pgpass_too_old() {
  [[ $MY_PGPASS -ot $PG_PGPASS ]]
}

pgpass_non_existant() {
  [[ ! -f $MY_PGPASS ]]
}

pgpass_copy_newer() {
  [[ $MY_PGPASS -ot $MY_PGPASS.copy ]]
}

talk() { echo 1>&2 "$*" ; }

if pgpass_copy_newer ; then
  cp $MY_PGPASS.copy $MY_PGPASS
  talk "$MY_PGPASS updated from copy"
elif pgpass_non_existant || pgpass_too_old || pgpass_too_small ; then
  sudo cp $PG_PGPASS $MY_PGPASS
  sudo chown $USER $MY_PGPASS
  sudo chmod 600 $MY_PGPASS
  cp $MY_PGPASS $MY_PGPASS.copy
  talk "$MY_PGPASS initialized"
fi