For convenience there are also single letter command-line option switches available for some parameters. They are described in Table 19.2. Some of these options exist for historical reasons, and their presence as a single-letter option does not necessarily indicate an endorsement to use the option heavily.
Short Option
Equivalent
-B x
shared_buffers = x
-d x
log_min_messages = DEBUGx
-e
datestyle = euro
-fb, -fh, -fi, -fm, -fn, -fo, -fs, -ft
enable_bitmapscan = off, enable_hashjoin = off, enable_indexscan = off, enable_mergejoin = off, enable_nestloop = off, enable_indexonlyscan = off, enable_seqscan = off, enable_tidscan = off
-F
fsync = off
-h x
listen_addresses = x
-i
listen_addresses = '*'
-k x
unix_socket_directories = x
-l
ssl = on
-N x
max_connections = x
-O
allow_system_table_mods = on
-p x
port = x
-P
ignore_system_indexes = on
-s
log_statement_stats = on
-S x
work_mem = x
-tpa, -tpl, -te
log_parser_stats = on, log_planner_stats = on, log_executor_stats = on
-W x
post_auth_delay = x