[Libguestfs] [PATCH] New tool: virt-list-filesystems

[Jim Meyering]

Richard W.M. Jones wrote:
> Subject: [PATCH] New tool: virt-list-filesystems
...

Another neat tool.  Nice.

> +# Try and mount each one, to see what's mountable.
> +foreach $dev (@partitions) {
> +    eval { $g->mount_ro ($dev, "/"); };
> +    my $mountable = $@ ? 0 : 1;
> +    $g->umount_all ();
> +    if ($mountable) {
> +	push @fses, $dev;
> +    } else {
> +	push @not_mountable, $dev;
> +    }
> +}
> +
> +foreach $dev (@fses) {
> +    print canonicalize($dev);
> +    if ($long) {
> +	my $fstype;
> +	eval { $fstype = $g->vfs_type ($dev); };
> +	if ($fstype) {
> +	    print " $fstype";
> +	} else {
> +	    print " unknown";
> +	}

A small stylistic suggestion: I would write the above 5 lines
using the ||= idiom, like this:

        $fstype ||= 'unknown';
        print " $fstype";

Note, that that's ok as long as you really want to use
'unknown' even when the incoming $fstype happens to evaluate
to 0, too.   But since that would never be a valid file system type,
this use of ||= is robust.

> +    }
> +    print "\n";
> +}