git and the loss of revision numbers

[monochrome]

sry forgot details:

source tree @ ead01bfe8

git -C /usr/src checkout gf20c0e331
error: pathspec 'gf20c0e331' did not match any file(s) known to git

what is the 'g' for?

git -C /usr/src checkout f20c0e331
M       sys/amd64/conf/GENERIC
HEAD is now at f20c0e331 caroot: drop $FreeBSD$ expansion from root bundle

yet I don't see any indication that anything changed, and now it wont 
update at all:

git -C /usr/src pull --ff-only
You are not currently on a branch.
Please specify which branch you want to merge with.
See git-pull(1) for details.

     git pull <remote> <branch>



On 12/28/20 7:56 PM, Pete Wright wrote:
> 
> On 12/28/20 4:38 PM, monochrome wrote:
>> what would be the git command for reverting source to a previous 
>> version using these numbers? for example, with svn and old numbers:
>> svnlite update -r367627 /usr/src
>>
> I will generally just checkout the short git hash like so in my local 
> checkout:
> $ git checkout gb81783dc98e6
> 
> you can quickly get the hashes by running "git log" from your checkout.
> 
> cheers,
> -pete
>