NAME

       expr - evaluate expressions

SYNOPSIS

       expr EXPRESSION
       expr OPTION

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.

AUTHOR

       Written by Mike Parker, James Youngman, and Paul Eggert.

REPORTING BUGS

       Report expr bugs to bug-coreutils@gnu.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/>

COPYRIGHT

       Copyright  ©  2013  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.

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.