[plug] Bash syntax error bad substitution

[David Dartnall]

It appears that one of the last Gutsy upgrades changed /bin/sh' from 
pointing to bash to pointing to dash, thereby messing up a bash script 
that I've been working on which worked perfectly on Sunday and which 
today produced the above error message. A change from #!/bin/sh to 
#!/bin/bash at the start of the script fixed the problem but I've spent 
half the day trying to work out what the hell went wrong!
What's dash anyway? What would possess them to change the 'standard' 
shell interpreter?
Any comments?

regards
Dave Dartnall