Check if database exists in PostgreSQL using shell

Question

I was wondering if anyone would be able to tell me about whether it is possible to use shell to check if a PostgreSQL database exists?

I am making a shell script and

Answer 1

I'm still pretty inexperienced with shell programming, so if this is really wrong for some reason, vote me down, but don't be too alarmed.

Building from kibibu's answer:

# If resulting string is not zero-length (not empty) then...
if [[ ! -z `psql -lqt | cut -d \| -f 1 | grep -w $DB_NAME` ]]; then
  echo "Database $DB_NAME exists."
else
  echo "No existing databases are named $DB_NAME."
fi