!!! set ECHO_HIDDEN on
    to print underlying sql-s

Usage:
  psql [OPTION]... [DBNAME [USERNAME]]

help:
  \? [commands]          show help on backslash commands
  \? options             show help on psql command-line options
  \? variables           show help on special variables
  \h [NAME]              help on syntax of SQL commands, * for all commands

General options:
    -h <dbhost>
        connect to <dbhost> host
    -d, --dbname=DBNAME      database name to connect to (default: "iharh")
        or connection URL
            postgresql://localhost
            https://psql-tips.org/psql_tips_all.html#tip013
    -U, --username <dbuser>
        connect by <dbuser> user

    -L filename
    --log-file=filename
        Write all query output into file filename, in addition to the normal output destination.
    -v assignment
    --set=assignment
    --variable=assignment
        Perform a variable assignment, like the \set meta-command. Note that you must separate name and value, if any, by an equal sign on the command line. To unset a variable,
        leave off the equal sign. To set a variable with an empty value, use the equal sign but leave off the value. These assignments are done during a very early stage of start-up,
        so variables reserved for internal purposes might get overwritten later.

    -c, --command=COMMAND
        run only single command (SQL or internal) and exit
    -f, --file=FILENAME
        execute commands from file, then exit.
        If you use the value - (hyphen) in the flag -f or --filename, psql will read commands and queries from the standard input.
        The read will end when reaching EOF command (CTRL+D) or the \q command.
            https://psql-tips.org/psql_tips_all.html#tip007
        or just redirect (with "<" or "|")
            https://psql-tips.org/psql_tips_all.html#tip009

    -l, --list
        list available databases, then exit 

    -e, --echo-queries
        display the query just before the query result in the standard output.
    -x, --expand
        expand the output for better readability
        https://psql-tips.org/psql_tips_all.html#tip043

    -s, --single-step
        stop after each command (for debug)

    -t, --tuples-only
        turn off printing column names and result row count footers

    -1, --single-transaction
        execute all in single transaction

samples
$ psql "service=myservice sslmode=require"
$ psql postgresql://dbmaster:5433/mydb?sslmode=require