expr(1) 						      General Commands Manual							   expr(1)

NAME

       expr - evaluate arguments as an expression

SYNOPSIS

       arguments

DESCRIPTION

       takes  arguments  as an expression, evaluates, then writes the result on the standard output.  Terms in the expression must be separated by
       blanks.	Characters special to the shell must be escaped.  Note that rather than the null string, is returned to  indicate  a  zero  value.
       Strings	containing  blanks  or other special characters should be quoted.  Integer-valued arguments can be preceded by a unary minus sign.
       Internally, integers are treated as 32-bit, 2's complement numbers.

       The operators and keywords are listed below.  Characters that need to be escaped are preceded by The list is in order of increasing  prece-
       dence with equal-precedence operators grouped within symbols.

       Returns the first expr if it is neither null nor otherwise returns the second expr.

			 In the UNIX 2003 environment, returns 0 if the first expr is null or and the second expr is null.

       Returns the first expr if neither expr is null or otherwise returns

       If both arguments are integers, and if the comparison is satisfied,
			 expr returns otherwise it returns expr returns the result of an integer comparison if both arguments are integers; other-
			 wise returns the result of a lexical comparison (note that and are identical, in that both test for equality).

       Addition or subtraction of decimal integer-valued arguments.

       Multiplication, division or remainder of decimal
			 integer-valued arguments producing an integer result.

       The matching operator
			 compares the first argument with the second argument which must be a regular expression.  expr supports the Basic Regular
			 Expression  syntax  (see regexp(5)), except that all patterns are ``anchored'' (i.e., begin with and, therefore, is not a
			 special character, in that context.  Normally, the matching operator returns the number of characters matched (0 on fail-
			 ure).	Alternatively, the pattern symbols can be used to return a portion of the first argument.

       The length of	 expr.

       Takes the substring of the first
			 expr, starting at the character specified by the second expr for the length given by the third expr.

       Returns the position in the first
			 expr which contains a character found in the second expr.

       Match is a prefix operator equivalent to the infix operator

       Grouping symbols. Any expression can be placed within parentheses.  Parentheses can be nested to a depth of as specified in the header file

EXTERNAL INFLUENCES

   Environment Variables
       determines the collating sequence used in evaluating regular expressions and the behavior of the relational operators when comparing string
       values.

       determines the interpretation of text as single- and/or multi-byte characters, and the characters matched by character class expressions in
       regular expressions.

       determines the language in which messages are displayed.

       If  or  is  not specified in the environment or is set to the empty string, the value of is used as a default for each unspecified or empty
       variable.  If is not specified or is set to the empty string, a default of "C" (see lang(5)) is used instead of If any internationalization
       variable contains an invalid setting, behaves as if all internationalization variables are set to "C" (see environ(5)).

       If is set to it enables the UNIX 2003 Standard environment.

   International Code Set Support
       Single- and multi-byte character code sets are supported.

RETURN VALUE

       As a side effect of expression evaluation, expr returns the following exit values:

	      Expression is neither null nor zero.

	      Expression is null or zero.

	      Invalid expression.

	      An error occurred while evaluating the expression.

DIAGNOSTICS

       Operator or operand errors

       Arithmetic attempted on a string

EXAMPLES

       Add 1 to the shell variable

       For  equal to either or just return the last segment of a path name (i.e., Beware of alone as an argument because expr interprets it as the
       division operator (see below):

       A better representation of the previous example.  The addition of the characters eliminates any ambiguity about the division  operator  and
       simplifies the whole expression:

       Return the number of characters in

WARNINGS

       After  argument	processing by the shell, expr cannot tell the difference between an operator and an operand except by the value.  If is an
       the command:

       resembles:

       as the arguments are passed to expr (and they will all be taken as the operator).  The following works:

AUTHOR

       was developed by OSF and HP.

SEE ALSO

       sh(1), test(1), environ(5), lang(5), regexp(5).

STANDARDS CONFORMANCE

																	   expr(1)