# Chapter 5: DISGCL Commands

This chapter describes several DISGCL commands.

## 5.1 Termination of DISGCL

The command EXIT terminates a DISGCL session.

The call is: | EXIT

## 5.2 Getting Help

The HELP command activates a menu for getting help.

The call is: | HELP

## 5.3 Including DISGCL Files

A DISGCL file can be included into another DISGCL file or DISGCL session with the statement

INCLUDE | 'file[.gcl]'

Additional notes:

- Up to 8 include files can be nested.
- DISGCL searches the current working directory for the filename. If the search fails, DISGCL searches the directory defined by the environment variable GCL_PATH.

## 5.4 Listing Variables

The command LIST list all defined variables.

The call is: | LIST [option] [v1, v2, ..., vn]

option | can have the values -s and -u. If -s is used, only system variables are listed, if -u is used, only user-defined variables are listed.
v1, v2, .., vn | are the names of variables. If no variables are specified, all defined variables are listed.

## 5.5 Freeing Variables

The command FREE deallocates the space allocated by arrays and strings.

The call is: | FREE v1, v2, ..., vn

v1, v2, .., vn | are the names of variables.

## 5.6 The PRINT Command

The command PRINT prints the value of an expression on the screen.

The call is: | PRINT expr1, expr2, ..., exprn

expr1, expr2, .., exprn | are expressions.

## 5.7 Logging Commands

The command LOGON defines a file where interactive commands will be logged.

The call is: | LOGON cfil

cfil | is a string containing a filename.

Additional notes:

- Logging can be terminated with the command LOGOFF.
- A log file can be executed with the DISGCL command, or can be included into a DISGCL session with the INCLUDE statement.
- If the file cfil already exists, a new file version will be created.

## 5.8 Creating Arrays

The commands BYTE, CHAR, INT, SHORT, FLOAT, DOUBLE and COMPLEX create corresponding arrays and initialize them with zeros.

The call is: | FLOAT list

list | is a list of arrays with dimension specifications separated by commas.

Example: | FLOAT A[10], B[5,10] creates an array A with 10 elements and a matrix B with 5 rows and 10 columns.

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