Comment # 25 on bug 1051465 from Franck Bui

(In reply to Thomas Blume from comment #24)
> 
> KERNEL=="nvme*", ENV{DEVTYPE}=="disk", IMPORT{program}="/bin/sh -c
> 'ID_SERIAL=$env{ID_SERIAL}; echo ID_SERIAL_TRUNCATED=${ID_SERIAL:0:16}'"
> 
> leaves ID_SERIAL_TRUNCATED empty:
> 
> because ID_SERIAL is not present in the shell environment.

Well that was an example which was supposed to show that string mangling could
be inlined in the rule file.

ID_SERIAL or whatever that needs to be used, is supposed to be retrieved from
sysfs by using the "$attr{xxx}" syntax.

Please note that we should make sure to not pollute the environment that is
already setup by the upstream rules. Therefore setting ID_SERIAL or ID_MODEL in
61-xxx is not a good idea.