Manual Reference Pages  - EXPR (1)

NAME

expr - evaluate expressions

CONTENTS

Synopsis
Description
Author
Copyright

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 © 2011 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.


GNU coreutils 8.12.197-032bb EXPR (1) September 2011
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