expr(1)

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

   GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
   Report expr translation bugs to <http://translationproject.org/team/>

COPYRIGHT

   Copyright  2016 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

   Full documentation at: <http://www.gnu.org/software/coreutils/expr>
   or available locally via: info '(coreutils) expr invocation'

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Free and Open Source Software