When you start SQL*Plus, it runs the glogin.sql site profile setup file and then runs the login.sql user profile setup file.

This section describes how to install and remove the SQL*Plus command-line Help.

• Installing SQL*Plus Command-Line Help

• Removing SQL*Plus Command-Line Help

$ sqlplus 
SQL> CONNECT SYSTEM
Enter password: system_password
SQL> @?/sqlplus/admin/help/helpdrop.sql

If you run an ED or EDIT command at the SQL*Plus prompt, then the system starts an operating system editor, such as ed, emacs, ned, or vi. However, the PATH environment variable must include the directory where the editor executable is located.

The HISTORY command enables users to run, edit, or delete previously used SQL*Plus, SQL, or PL/SQL commands from the history list in the current session. You can enable or disable the history of commands issued in the current SQL*Plus session.

When you start the editor, the current SQL buffer is placed in the editor. When you exit the editor, the changed SQL buffer is returned to SQL*Plus.

You can specify which editor should start by defining the SQL*Plus _EDITOR variable. You can define this variable in the glogin.sql site profile or the login.sql user profile. Alternatively, you can define it during the SQL*Plus session. For example, to set the default editor to vi, run the following command:

SQL> DEFINE _EDITOR=vi

If you do not set the _EDITOR variable, then the value of either the EDITOR or the VISUAL environment variable is used. If both environment variables are set, then the value of the EDITOR variable is used. If _EDITOR, EDITOR, and VISUAL are not specified, then the default editor is vi. The defined editor is used in the edit option of the HISTORY command. Consider the following SQL statements:

SQL> hist
1 select * from dual;
2 desc dual

To open the first entry in the above SQL statements in the vi editor, use the following command:

SQL> hist 1 edit

When you start the editor, SQL*Plus uses the afiedt.buf temporary file to pass text to the editor. You can use the SET EDITFILE command to specify a different file name. For example:

SQL> SET EDITFILE /tmp/myfile.sql

SQL*Plus does not delete the temporary file.

Using the HOST command or an exclamation point (!) as the first character after the SQL*Plus prompt causes subsequent characters to be passed to a subshell. The SHELL environment variable sets the shell used to run operating system commands. The default shell is the Bourne shell. If the shell cannot be run, then SQL*Plus displays an error message.

To return to SQL*Plus, run the exit command or press Ctrl+D.

For example, to run a single command, use the following command syntax:

SQL> ! command

In this example, command represents the operating system command that you want to run.

To run multiple operating system commands from SQL*Plus, run the HOST or ! command. Press Enter to return to the operating system prompt.