A lot of people actually ask me why sql*plus doesn’t have a help feature like man in UNIX. Actually it does for all sql*plus command but not for the SQL language. Below I will show some help commands for SQL*Plus:

SQL> ?

HELP
—-

Accesses this command line help system. Enter HELP INDEX or ? INDEX
for a list of topics. In iSQL*Plus, click the Help button to display
iSQL*Plus online help.
You can view SQL*Plus resources at http://otn.oracle.com/tech/sql_plus/
and the Oracle Database Library at http://otn.oracle.com/documentation/

HELP|? [topic]
SQL> ? index

Enter Help [topic] for help.

@ COPY PAUSE SHUTDOWN
@@ DEFINE PRINT SPOOL
/ DEL PROMPT SQLPLUS
ACCEPT DESCRIBE QUIT START
APPEND DISCONNECT RECOVER STARTUP
ARCHIVE LOG EDIT REMARK STORE
ATTRIBUTE EXECUTE REPFOOTER TIMING
BREAK EXIT REPHEADER TTITLE
BTITLE GET RESERVED WORDS (SQL) UNDEFINE
CHANGE HELP RESERVED WORDS (PL/SQL) VARIABLE
CLEAR HOST RUN WHENEVER OSERROR
COLUMN INPUT SAVE WHENEVER SQLERROR
COMPUTE LIST SET XQUERY
CONNECT PASSWORD SHOW
SQL> ? get

GET
—

Loads a SQL statement or PL/SQL block from a script into the SQL buffer.
In iSQL*Plus click the Load Script button to load a script into the
Workspace. The buffer has no command history list and does not record
SQL*Plus commands.

GET [FILE] file_name[.ext] [LIST | NOLIST]

Not available in iSQL*Plus
SQL> ? clear

CLEAR
—–

Resets or erases the current value or setting for the specified option.

CL[EAR] option …

where option represents one of the following clauses:
BRE[AKS]
BUFF[ER]
COL[UMNS]
COMP[UTES]
SCR[EEN]
SQL
TIMI[NG]

CLEAR SCREEN is not available in iSQL*Plus
SQL>