expr - evaluate expressions
--help display this help and exit
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 of STRING
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.
expr exits with:
0 if the expression is neither null nor 0; 1 if the expression
is null or 0; or 2 for invalid expressions.
Written by Mike Parker.
Report bugs to <firstname.lastname@example.org>.
Copyright (C) 2000 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is
NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
The full documentation for expr is maintained as a Texinfo manual. If
the info and expr programs are properly installed at your site, the
should give you access to the complete manual.
GNU sh-utils 2.0.11 July 2001 EXPR(1)
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