> For the complete documentation index, see [llms.txt](https://docs.postgresql.tw/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.postgresql.tw/server-administration/server-configuration/short-options.md).

# 20.18. Short Options

For convenience there are also single letter command-line option switches available for some parameters. They are described in [Table 19.2](https://www.postgresql.org/docs/12/runtime-config-short.html#RUNTIME-CONFIG-SHORT-TABLE). 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.

#### **Table 19.2. Short Option Key**

| Short Option                                           | Equivalent                                                                                                                                                                                                    |
| ------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `-B`` `*`x`*                                           | `shared_buffers =`` `*`x`*                                                                                                                                                                                    |
| `-d`` `*`x`*                                           | `log_min_messages = DEBUG`*`x`*                                                                                                                                                                               |
| `-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`*                                                                                                                                                                                   |


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