expr (1g)

名称

expr - evaluate expressions

用法概要

expr EXPRESSION
expr OPTION

描述

User Commands                                             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.   EXPRES-
     SION 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



GNU coreutils 8.16   Last change: March 2012                    1






User Commands                                             EXPR(1)



          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  num-
     bers,  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/core-
     utils/>
     General  help  using GNU software: <http://www.gnu.org/geth-
     elp/>
     Report  expr  translation  bugs  to  <http://translationpro-
     ject.org/team/>

COPYRIGHT
     Copyright  (C)  2012 Free Software Foundation, Inc.  License



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User Commands                                             EXPR(1)



     GPLv3+:     GNU     GPL     version     3      or      later
     <http://gnu.org/licenses/gpl.html>.
     This  is  free  software:  you are free to change and redis-
     tribute it.  There is NO WARRANTY, to the  extent  permitted
     by law.


ATTRIBUTES
     See   attributes(5)   for   descriptions  of  the  following
     attributes:

     +---------------+--------------------+
     |ATTRIBUTE TYPE |  ATTRIBUTE VALUE   |
     +---------------+--------------------+
     |Availability   | file/gnu-coreutils |
     +---------------+--------------------+
     |Stability      | Uncommitted        |
     +---------------+--------------------+
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.



NOTES
     This  software  was   built   from   source   available   at
     https://java.net/projects/solaris-userland.    The  original
     community       source       was       downloaded       from
     http://ftp.gnu.org/gnu/coreutils/coreutils-8.16.tar.xz

     Further  information about this software can be found on the
     open source community  website  at  http://www.gnu.org/soft-
     ware/coreutils/.

















GNU coreutils 8.16   Last change: March 2012                    3