### Category

Linux Command

### Usage

expr EXPRESSION

### Manual

--help display this help and exit

--version

output version information and exit

Print the value of EXPRESSION to standard output. A blank line below

separates increasing precedence groups. 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

ARG1 is less than ARG2

ARG1 <= ARG2

ARG1 is less than or equal to ARG2

ARG1 = ARG2

ARG1 is equal to ARG2

ARG1 != ARG2

ARG1 is unequal to ARG2

ARG1 >= ARG2

ARG1 is greater than or equal to ARG2

ARG1 > ARG2

ARG1 is greater than ARG2

ARG1 + ARG2

arithmetic sum of ARG1 and ARG2

ARG1 - ARG2

arithmetic difference of ARG1 and ARG2

ARG1 * ARG2

arithmetic product of ARG1 and ARG2

ARG1 / ARG2

arithmetic quotient of ARG1 divided by ARG2

ARG1 % ARG2

arithmetic remainder of ARG1 divided by 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

+ TOKEN

interpret TOKEN as a string, even if it is a

keyword like â€˜matchâ€™ or an operator like â€˜/â€™

( 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 lexicographi-

cal. Pattern matches return the string matched between \( and \) or

null; if \( and \) are not used, they return the number of characters

matched or 0.

Exit status is 0 if EXPRESSION is neither null nor 0, 1 if EXPRESSION

is null or 0, 2 if EXPRESSION is syntactically invalid, and 3 if an

error occurred.

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