# Keyword Reference

# If...Then

Conditionally run a single statement.

If <expression> Then statement

## Parameters

expression | If the expression is true, the statement is executed.

## Remarks

This version of the If statement is used to execute a single statement without the overhead of an EndIf.
The expression can contain the boolean operators of And, Or, and Not as well as the logical operators <, <=, >, >=, =, ==, and <> grouped with parentheses as needed.

## Related

If...Else...EndIf, Select...Case...EndSelect, Switch...EndSwitch, Ternary

## Example

    #include <MsgBoxConstants.au3>

    ; Terminates script if no command-line arguments
    If $CmdLine[0] = 0 Then Exit

    ; Alternative:
    If $CmdLine[0] = 0 Then
        Exit
    EndIf

    MsgBox($MB_SYSTEMMODAL, "", "Script has command-line arguments.")