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    BusyBox v1.29.3 (2018-11-02 15:37:50 PDT) multi-call binary.
    Usage: expr EXPRESSION
    Print the value of EXPRESSION to stdout
    EXPRESSION may be:
    	ARG1 | ARG2	ARG1 if it is neither null nor 0, otherwise ARG2
    	ARG1 & ARG2	ARG1 if neither argument is null or 0, otherwise 0
    	ARG1 < ARG2	1 if ARG1 is less than ARG2, else 0. Similarly:
    	ARG1 <= ARG2
    	ARG1 = ARG2
    	ARG1 != ARG2
    	ARG1 >= ARG2
    	ARG1 > ARG2
    	ARG1 + ARG2	Sum of ARG1 and ARG2. Similarly:
    	ARG1 - ARG2
    	ARG1 * ARG2
    	ARG1 / ARG2
    	ARG1 % ARG2
    	STRING : REGEXP		Anchored pattern match of REGEXP in STRING
    	match STRING REGEXP	Same as STRING : REGEXP
    	substr STRING POS LENGTH Substring of STRING, POS counted from 1
    	index STRING CHARS	Index in STRING where any CHARS is found, or 0
    	length STRING		Length of STRING
    	quote TOKEN		Interpret TOKEN as a string, even if
    				it is a keyword like 'match' or an
    				operator like '/'
    	(EXPRESSION)		Value of EXPRESSION
    Beware that many operators need to be escaped or quoted for shells.
    Comparisons are arithmetic if both ARGs are numbers, else
    lexicographical. Pattern matches return the string matched between
    \( and \) or null; if \( and \) are not used, they return the number
    of characters matched or 0.
    
    



Designed by SanjuD(@ngineerbabu)