Execute TDengine CLI program `taos` directly from the Linux shell to connect to the TDengine service and enter the TDengine CLI interface, as shown in the following example.

```text
$ taos

taos> show databases;
              name              |       create_time       | vgroups |        ntables        | replica | strict |  duration  |              keep              |   buffer    |  pagesize   |    pages    |   minrows   |   maxrows   | comp | precision |   status   |           retention            | single_stable | cachemodel  |  cachesize  | wal_level | wal_fsync_period | wal_retention_period |  wal_retention_size   | wal_roll_period |     wal_seg_size      |
=========================================================================================================================================================================================================================================================================================================================================================================================================================================================================
 information_schema             | NULL                    |    NULL |                    14 |    NULL | NULL   | NULL       | NULL                           |        NULL |        NULL |        NULL |        NULL |        NULL | NULL | NULL      | ready      | NULL                           | NULL          | NULL        |        NULL |      NULL |             NULL |                 NULL |                  NULL |            NULL |                  NULL |
 performance_schema             | NULL                    |    NULL |                     3 |    NULL | NULL   | NULL       | NULL                           |        NULL |        NULL |        NULL |        NULL |        NULL | NULL | NULL      | ready      | NULL                           | NULL          | NULL        |        NULL |      NULL |             NULL |                 NULL |                  NULL |            NULL |                  NULL |
 db                             | 2022-08-04 14:14:49.385 |       2 |                     4 |       1 | off    | 14400m     | 5254560m,5254560m,5254560m     |          96 |           4 |         256 |         100 |        4096 |    2 | ms        | ready      | NULL                           |         false | none        |           1 |         1 |             3000 |                    0 |                     0 |               0 |                     0 |
Query OK, 3 rows in database (0.019154s)

taos>
```