'test' utility behavior question.

Eric Blake eblake@redhat.com
Mon Aug 30 17:47:00 GMT 2010


On 08/30/2010 11:27 AM, Oleksandr Gavenko wrote:
>   $ /bin/test -d && echo ok
> ok
> $ /bin/test -d '' && echo ok || echo must_be_error
> must_be_error

Both of these results match POSIX.  Remember, POSIX describes different 
behaviors for one argument than for two arguments (for the one-argument 
case, the string "-d" is non-empty, so the result must be 0; for the 
two-argument case, the string "-d" is a unary operator, and there is no 
directory named '').

> if [ -d $dir ]; then

The bug is in your script.  You forgot to use quoting or a bashism. 
Either of these fixes will correct your script (although the latter 
requires bash):

if [ -d "$dir" ]; then

if [[ -d $dir ]]; then

This is not cygwin-specific.

-- 
Eric Blake   eblake@redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org

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