FAI ainsl exit code, softupdate, scripts/FAIBASE/10-misc

[Rob]

  This is not a show-stopper, but I am curious to find the thoughts of 
users and developers about this behavior.  I've searched the website and 
archives and I generally DO follow the email list, but I haven't heard 
of this topic before.   First, a real problem is the ainsl manpage, 
which doesn't document the exit codes of the ainsl command.  Second, I 
differ philosophically with the idea of ainsl returning an error code to 
the caller if the line already exists in the file.

My actual questions are: What's the best way to have 
scripts/FAIBASE/10-misc return success on softupdate?   Should the 
module list be checked on every softupdate?  Whether or not, I think 
extra logic would be needed in 10-misc to avoid reporting errors when in 
fact no errors exist.  (To be idealistic, I would like to see ainsl 
return 0 if the line previously existed in the file.)


Details:

When running softupdate,  scripts/FAIBASE/10-misc always reports an error.

It appears this is because, at the beginning of the script, these 
commands are issued:

     error=0 ; trap "error=$((error|1))" ERR

which causes the script to return non-zero (error condition) whenever a 
simple command in the script returns non-zero.  Next, the 10-misc script 
uses ainsl to check /etc/modules:

     for module in $MODULESLIST; do
         ainsl -a $target/etc/modules "^$module$"
     done

Upon softupdate, the modules should already be in the file, which causes 
the $error variable to be set, which is then returned as an exit code.   
This is because ainsl returns an error (1) if the line is already in the 
file [code from ainsl]:

     exit 1 if $found; # nothing to append

which returns an error condition if the file is already in the desired 
state. (This doesn't seem intuitively correct to me.  My intent is to 
ensure the line is in the file, I don't care if the line existed before 
or not).  Because of this behavior of ainsl and the error trapping code 
in 10-misc, 10-misc always reports an error on softupdate.

The return values of ainsl are not documented on the ainsl manpage.

Thank you for FAI and your help and ideas!
Rob