    IF(I)                         5/2/74                        IF(I)

    NAME
         if -  conditional command

    SYNOPSIS
         if expr command [ arg ... ]

    DESCRIPTION
         If  evaluates the expression expr, and if its value is true,
         executes the given command with the given arguments.

         The following primitives are used to construct the expr:

         -r file      true if the file exists and is readable.

         -w file      true if the file exists and is writable.

         s1 = s2      true if the strings s1 and s2 are equal.

         s1 != s2     true if the strings s1 and s2 are not equal.

         { command }  The bracketed command is executed to obtain the
                      exit  status.   Status zero is considered true.
                      The command must not be another if.

         These primaries may be combined with  the  following  opera-
         tors:

         !            unary negation operator

         -a           binary and operator

         -o           binary or operator

         ( expr )     parentheses for grouping.

         -a has higher precedence than -o.  Notice that all the oper-
         ators and flags are separate arguments to if and hence  must
         be  surrounded  by spaces.  Notice also that parentheses are
         meaningful to the Shell and must be escaped.

    SEE ALSO
         sh(I), find(I)

    BUGS

                                  - 1 -