git detached head: how I restore texts (sometimes)

abstract

The concern is documenting an accidental discovery of the DETACHED HEAD state

1. enter detached HEAD

• note that HEAD is the term from data structure terminology for graph-types like lists or DAGs
• it denotes the beginning point where the traverse can begin (TAIL being the end)
• in git: HEAD === active branch — only 1 branch can be active, pointing to the latest commit
• in powershell, from the main folder of the git project get the name of the active branch

gc ./.git/HEAD
ref: refs/heads/master

• if you however checkout a particular commit with the its <sha> you'll enter a state of DETACHED HEAT

The detached HEAD state is useful for revisiting old states, and sometimes for short-term work that you are not sure you will keep. Other than that you probably want to avoid it. — https://stackoverflow.com/a/2467564/11082684

• if you checkout only <sha> you will create a DETACHED HEAD

git checkout <sha>

2. rules

• you can’t merge detached HEAD
• this is just a peek into the past, but it is very transient
• once you checkout back to master, the detached HEAD dissapears again

3. usecase

• in my markdown notes, sometimes I commit en-masse
• in some of those commits there are files mistakenly re-pasted, edited
• need to check the initial commit of the affected file
• this is the case for DETACHED HEAD
• get the file history with

git log --pretty=format:\"%C(auto)%h%d%Creset %C(cyan)(%ci)%Creset %C(green)%cn <%ce>%Creset %s\" --name-status --date=short --all --full-history -- foo.txt

• checkout a detached head

git checkout <sha>

• open foo.txt to se if that is what you were looking for

4. sources

• https://stackoverflow.com/a/2467564/11082684