PostgreSQL REPL
psql is a terminal-based front-end to PostgreSQL.
# to get some help
db=# \?
# describe (options)
# S - Show system options
# + - Addtional Details
db=# \d
# Or describe an specific table
db=# \d "<schema>.<table>"
# list schemas
db=# \dn
# Output format
db=# \x auto