postinst script

[Zvi Dubitzky <DUBI@il.ibm.com>]

Hi

I have a command line in postinst script of a package that works ok 
outside a package install context .
one line is causing an error :

cat  /proc/file  | grep XY   > file 

without the grep - no error 
with the grep the postinstall terminates with error(below) . 

dpkg: error processing <package>(--install):
 subprocess post-installation script returned error exit status 1
Errors were encountered while processing:

Any idea why or  limitations of postinst script

thanks

Zvi Dubitzky 
Email:dubi@il.ibm.com