[Guide to AmigaDOS 3\IF] 
 

IF

Format: IF [NOT] [WARN] [ERROR] [FAIL] [<string> EQ|GT|GE <string>] [VAL] [EXISTS <filename>] Template: NOT/S, WARN/S, ERROR/S, FAIL/S, EQ/K, GT/K, GE/K, VAL/S, EXISTS/K Purpose: To evaluate conditional operations in script files. Path: Internal Specification: In a script file, IF, when its conditional is true, carries out all the subsequent commands until an ENDIF or ELSE command is found. When the conditional is not true, execution skips directly to the ENDIF or to an ELSE. The conditions and commands in IF and ELSE blocks can span more than one line before their corresponding ENDlFs. ELSE is optional, and nested IFs jump to the nearest ENDIF. The additional keywords are as follows:

NOT

Reverses the interpretation of the result.

WARN

True if previous return code is greater than or equal to 5.

ERROR

True if previous return code is greater than or equal to 10; only available if you set FAILAT to greater than 10.

FAIL

True if previous return code is greater than or equal to 20; only available if you set FAILAT to greater than 20.

<a> EQ <b>

True if the text of a and b is identical (disregarding case).

EXISTS <file>

True if the file exists. If more than one of the three condition-flag keywords (WARN, ERROR, FAIL) are given, the one with the lowest value is used. IF supports the GT (greater than) and GE (greater than or equal to) comparisons. Normally, the comparisons are performed as string comparisons. However, if the VAL option is specified, the comparison is a numeric comparison. You can use NOT GE for LT and NOT GT for LE. You can use local or global variables with IF by prefacing the variable name with a $ character. Example 1: IF EXISTS Work/Prog TYPE Work/Prog ELSE ECHO "It's not here" ENDIF If the file Work/Prog exists in the current directory, then AmigaDOS displays it. Otherwise, AmigaDOS displays the message "It's not here" and continues after the ENDIF. Example 2: IF ERROR SKIP errlab ENDIF ECHO "No error" LAB errlab If the previous command produced a return code greater than or equal to 10, then AmigaDOS skips over the ECHO command to the errlab label. See also: EXECUTE FAILAT LAB QUIT SKIP


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