expr(1)

NAME
     expr - evaluate experession

SYNOPSIS
     expr arg ...

EXAMPLES

     x=`expr $x + 1`     # Add 1 to shell variable x

DESCRIPTION

     Expr computes the value of its argument and writes the result on standard
     output.   The  valid  operators,  in  order of increasing precedence, are
     listed below.  Operators grouped by {...} have the same precedence.   The
     operators  are:  |,  &,  {<,  <=, ==, !=, >=, >}, {+, -}, *, /, %, and :.
     Parentheses are permitted.

SEE ALSO
     sh(1), test(1).