I just installed grml-crypt and grml-shlib packages on Ubuntu Hardy Heron 
(8.04). 

ii  grml-crypt          0.15           wrapper around cryptsetup-luks
ii  grml-shlib          1.02.13        Generic shell library used in grml 
scripts

Apparently, Ubuntu uses dash as default shell for /bin/sh as it states to be 
POSIX compliant. 
But when I call grml-crypt (for example) with dash, the following happens: 

bene@hp:~/Desktop$ sudo /usr/sbin/grml-crypt
/etc/grml/sh-lib: 37: function: not found
[... similar lines omitted here ...]
/etc/grml/sh-lib: 68: function: not found
[: 78: Illegal number: -a
/etc/grml/sh-lib: 81: function: not found
/etc/grml/sh-lib: 86: vprint: not found
[... similar lines omitted here ...]
/etc/grml/sh-lib: 104: vprint: not found
/etc/grml/sh-lib: 106: function: not found
PANIC:
/etc/grml/sh-lib: 122: _syslog: not found
Terminated
bene@hp:~/Desktop$

Using bash, the behaviour is as intended:

bene@hp:~/Desktop$ sudo /bin/bash /usr/sbin/grml-crypt
Usage: "grml-crypt" [OPTIONS] action <device/file> [mountpoint]

grml-crypt is a wrapper around cryptsetup with LUKS support to format a device
[...]