How to view the usage of some commands in SQL * plus

How to view the usage of some commands in SQL * plus

Sometimes I forget the usage of some commands when using SQL * plus. In fact, we don't have to look up anything. We just need to check it in SQL * plus,

Use help |? Parameter

For example, in SQL * plus:

SQL> help column

COLUMN
------
Specifies display attributes for a given column, such:
-Text for the column heading
-Alignment for the column heading
-Format for NUMBER data
-Wrapping of column data
Also lists the current display attributes for a single column
Or all columns.

COL [UMN] [{column | expr} [option...]

Where option represents one of the following clses:
ALI [AS] alias
CLE [AR]
ENTMAP {ON | OFF}
FOLD_A [FTER]
FOLD_ B [EFORE]
FOR [MAT] format
HEA [DING] text
JUS [weight] {L [EFT] | C [ENTER] | R [IGHT]}
LIKE {expr | alias}
NEWL [INE]
NEW_V [ALUE] variable
NOPRI [NT] | PRI [NT]
NUL [L] text
OLD_V [ALUE] variable
ON | OFF
WRA [PPED] | WOR [D_WRAPPED] | TRU [NCATED]

Can also be used ?, As follows:

SQL>? Show

SHOW
----
Shows the value of a SQL * Plus system variable, or the current
SQL * Plus environment. SHOW SGA requires a DBA privileged login.

SHO [W] option

Where option represents one of the following terms or clses:
System_variable
ALL
BTI [TLE]
CON_ID
CON_NAME
ERR [ORS] [{FUNCTION | PROCEDURE | package body | TRIGGER
| VIEW | type body | DIMENSION | java class} [schema.] name]
LNO
PARAMETERS [parameter_name]
PDBS
PNO
RECYC [LEBIN] [original_name]
REL [statement]
REPF [OOTER]
REPH [EADER]
SGA
SPOO [L]
SPPARAMETERS [parameter_name]
SQLCODE
TTI [TLE]
USER

The red statement is the SQL statement of the command, and the following describes some of its parameters.