expr
evaluate expressions
Synopsis
expr
EXPRESSION
expr OPTION
add an example, a script, a trick and tips
examples
source
echo `expr 1 + 3`
echo `expr 6 \*
2`
source
echo "expr 1 +
3 " `expr 1 +
3`
echo "expr 2 -
1 " `expr 2 -
1`
echo "expr 10 /
2 " `expr 10 /
2`
echo "expr 10 / 2
" `expr 10 / 2`
echo "expr 20 %
3 " `expr 20 %
3`
echo "expr 10
\* 3 " `expr 10
\* 3`
#expr 10 \* 3 - Multiplication use \*
and not * since its wild card.
description
--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
’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.
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.
copyright
Copyright © 2012 Free Software Foundation, Inc. License GPLv3+:
GNU GPL version 3 or later
<http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute
it. There is NO WARRANTY, to the extent permitted by law.
reporting bugs
Report expr bugs to bug-coreutils[:at:]gnu[:dot:]org
GNU coreutils home page:
<http://www.gnu.org/software/coreutils/>
General help using GNU software:
<http://www.gnu.org/gethelp/>
Report expr translation bugs to
<http://translationproject.org/team/>
see also
The full
documentation for expr is maintained as a Texinfo
manual. If the info and expr programs are
properly installed at your site, the command
info
coreutils 'expr invocation'
should give you
access to the complete manual.
author
Written by Mike
Parker, James Youngman, and Paul Eggert.