Unix/Linux Go Back    


BSD 2.11 - man page for expr (bsd section 1)

Linux & Unix Commands - Search Man Pages
Man Page or Keyword Search:   man
Select Man Page Set:       apropos Keyword Search (sections above)


EXPR(1) 										  EXPR(1)

NAME
       expr - evaluate arguments as an expression

SYNOPSIS
       expr arg ...

DESCRIPTION
       The  arguments are taken as an expression.  After evaluation, the result is written on the
       standard output.  Each token of the expression is a separate argument.

       The operators and keywords are listed below.  The list is in order  of  increasing  prece-
       dence, with equal precedence operators grouped.

       expr | expr
	      yields  the  first  expr if it is neither null nor `0', otherwise yields the second
	      expr.

       expr & expr
	      yields the first expr if neither expr is null or `0', otherwise yields `0'.

       expr relop expr
	      where relop is one of < <= = != >= >, yields `1' if  the	indicated  comparison  is
	      true, `0' if false.  The comparison is numeric if both expr are integers, otherwise
	      lexicographic.

       expr + expr
       expr - expr
	      addition or subtraction of the arguments.

       expr * expr
       expr / expr
       expr % expr
	      multiplication, division, or remainder of the arguments.

       expr : expr
	      The matching operator compares the string first argument with the  regular  expres-
	      sion  second argument; regular expression syntax is the same as that of ed(1).  The
	      \(...\) pattern symbols can be used to select a  portion	of  the  first	argument.
	      Otherwise,  the  matching  operator yields the number of characters matched (`0' on
	      failure).

       ( expr )
	      parentheses for grouping.

       Examples:

       To add 1 to the Shell variable a:

	      a=`expr $a + 1`

       To find the filename part (least significant part) of the pathname stored in  variable  a,
       which may or may not contain `/':

	      expr $a : '.*/\(.*\)' '|' $a

       Note the quoted Shell metacharacters.

SEE ALSO
       sh(1), test(1)

DIAGNOSTICS
       Expr returns the following exit codes:

	    0	 if the expression is neither null nor `0',
	    1	 if the expression is null or `0',
	    2	 for invalid expressions.

7th Edition				  April 29, 1985				  EXPR(1)
Unix & Linux Commands & Man Pages : ©2000 - 2018 Unix and Linux Forums


All times are GMT -4. The time now is 11:37 PM.