




Command:   test, [ - test for a condition
Syntax:    test expr
           [ expr ]
Flags:     (none)
Example:   test -r file             # See if file is readable

     Test checks to see if files exist, are readable, etc.  and  returns
an  exit  status  of  zero  if  true  and  nonzero  if false.  The legal
operators are

      -r file     true if the file is readable
      -w file     true if the file is writable
      -x file     true if the file is executable
      -f file     true if the file is not a directory
      -d file     true if the file is a directory
      -s file     true if the file exists and has a size > 0
      -t fd       true if file descriptor fd (default 1) is a terminal
      -z s        true if the string s has zero length
      -n s        true if the string s has nonzero length
      s1 = s2     true if the strings s1 and s2 are identical
      s1 != s2    true if the strings s1 and s2 are different
      m -eq m     true if the integers m and n are numerically equal

The operators -gt, -ge, -ne, -le, and -lt may be used  as  well.   These
operands  may  be  combined  with  -a  (Boolean and), -o (Boolean or), !
(negation). The priority of -a is higher than that  of  -o.  Parentheses
are  permitted,  but  must  be  escaped to keep the shell from trying to
interpret them.






























                                                                        

