words

The if command in Windows batch files has some strange implications. One problem is that parentheses take on special meaning.

I first ran into this problem because my batch file would terminate shortly after showing, “folder unexpected at this time“.

A very basic if command might look like this:

C:\>if exist C:\ ( echo The C drive exists )
The C drive exists

However, placing parentheses inside the echo statement will entirely confuse CMD:

C:\>if exist C:\ ( echo The C drive exists (no, really) )
) was unexpected at this time.

Well, that sort of makes sense. It becomes confusing when the last word in your echo command is something more general, like the word ‘folder’:

C:\>if exist C:\Windows ( echo Found the Windows (on C:) folder )
folder was unexpected at this time.

This is actually the classic %%i was unexpected at this time error.

One solution is to put double quotes around the message to be echoed:

C:\>if exist C:\Windows ( echo "Found the Windows (on C:) folder" )
"Found the Windows (on C:) folder"

The drawback here is that the double quotes appear in the output. A better option is to use the caret (^) escape character:

C:\>if exist C:\Windows ( echo Found the Windows ^(on C:^) folder )
Found the Windows (on C:) folder

I want to install Graphviz on a machine in order to get access to the dot diagram generator. However, I don’t have root access on this box, so I want to install it in my home directory, under ~/bin/graphviz. To do this, call the configure script with a few arguments to change the installation directory:

./configure --exec_prefix=$HOME/bin/graphviz/ --mandir=$HOME/man \
--prefix=$HOME/bin/graphviz/

Then make, and install:

make
make install

Even though make install gives me an error, “/usr/bin/ld: cannot find -lperl“, I find that Graphviz now appears under ~/bin/graphviz:

ls ~/bin/graphviz/
bin/  include/  lib/  share/

On a different box, I was unable to get this far. I received this error:

libtool: install: error: cannot install `libgraph.la' to a directory not ending in /usr/local/lib

This is caused by an out-of-date libtool.

libtool --version
ltmain.sh (GNU libtool) 1.4 (1.920 2001/04/24 23:26:18)

Problem

I created an XML stylesheet which I wanted to place on a local Samba share. In the XML file to be transformed, I placed a file:// URI in the xml-stylesheet tag, but it wouldn’t work in Firefox. Internet Explorer would happily format the content as expected, but Firefox simply displayed a rather uninformative error:

Error loading stylesheet: (null)

Cause

As it turns out, I was formatting the URI incorrectly.

Solution

Proper URI formatting for the file protocol requires three slashes to establish an empty authority or host segment, followed by the full path, with all backslashes converted to forward slashes. Since it was a path to a file on a local Samba server, which normally begins with two backslashes, this means I needed a total of five forward slashes following file:!

So, given a Windows-style path such as:

\\myserver\mypath\mystylesheet.xslt

The corresponding URI would be:

file://///myserver/mypath/mystylesheet.xslt

Yielding an xml-stylesheet tag like

<?xml-stylesheet type="text/xsl"
                 href="file://///myserver/mypath/mystylesheet.xslt">

Reference

MozillaZine: Links to local pages don’t work

I’m running VMware Workstation 6.5 under Windows Vista. I have Ubuntu 8.04 installed. I found a tip on how to enable the mouse scroll wheel, but I found that it switched my mouse over to Ubuntu control. That is to say, my mouse acceleration changed, and I was no longer able to seamlessly move my mouse out of the VMware window.

In the end, it turns out to be critical that VMware Mouse be retained as the input device identifier in /etc/X11/xorg.conf:

Section "InputDevice"
	Identifier	"VMware Mouse"
	Driver		"vmmouse"
	Option		"CorePointer"
	Option		"Device"	"/dev/input/mice"
	Option		"Protocol"	"ImPS/2"
	Option		"Buttons"	"5"
	Option		"ZAxisMapping"	"4 5"
EndSection