no help needed anymore...thx
The
test command evaluates the expression expr and, if its value is True, returns a zero (true) exit status; otherwise, a nonzero (false) exit status is returned. test also returns a nonzero exit status if there are no arguments. The following primitives are used to construct expr: -r file True if file exists and is readable.
-w file True if file exists and is writable.
-x file True if file exists and is executable.
-f file True if file exists and is a regular file.
-d file True if file exists and is a directory.
-c file True if file exists and is a character special file.
-b file True if file exists and is a block special file.
-p file True if file exists and is a named pipe (fifo).
-u file True if file exists and its set-user-ID bit is set.
-g file True if file exists and its set-group-ID bit is set.
-k file True if file exists and its sticky bit is set.
-s file True if file exists and has a size greater than zero.
-h file True if file exists and is a symbolic link.
-t [fildes] True if the open file whose file descriptor number is fildes (1 by default) is associated with a terminal device.
-z s1 True if the length of string s1 is zero.
-n s1 True if the length of the string s1 is non-zero.
s1 = s2 True if strings s1 and s2 are identical.
s1 != s2 True if strings s1 and s2 are not identical.
s1 True if s1 is not the null string.
n1 -eq n2 True if the integers n1 and n2 are algebraically equal. Any of the comparisons -ne, -gt, -ge, -lt, and -le can be used in place of -eq.
These primaries can be combined with the following operators: ! Unary negation operator.
-a Binary AND operator.
-o Binary OR operator (-a has higher precedence than -o).
( expr ) Parentheses for grouping.
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by the way, go back to the Input by while->break....
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also have a look here...
http://www.washington.edu/computing/...g/125/ctl.html