Alice: history simplification

In this laboratory, our best writer will make some changes, but simplifying the log before merging her working branch with main to avoid generating noise.

Lab

• Alice updated the title of the first chapter, but after taking some time for drinking coffee, she prefers to ensure she is in the correct directory:

cd alice/book
git status
git log --oneline

• Everything looks fine, so she continues editing the rest of the chapters

sed -i '1s/^/## Chapter two\n\n/' chapter-02.md
cat chapter-02.md
git add chapter-02.md
git commit -m "Added chapter number (2)"

sed -i '1s/^/## Chapter three\n\n/' chapter-03.md
cat chapter-03.md
git add chapter-03.md
git commit -m "Added chapter number (3)"

sed -i '1s/^/## Chapter four\n\n/' chapter-04.md
cat chapter-04.md
git add chapter-04.md
git commit -m "Added chapter number (4)"

• Cool. Time to merge the changes with main. But Alice thinks the different log messages are mostly noise, that could be simplified. So she rewrites the lasts four commits into a single one by using an interactive rebase

git rebase -i HEAD~4

• After this command, the default text editor shows one line with each of the last four commits. Alice could change the order of the commits by moving those lines, for example. By default, the command applied to each commit will be pick, that would keep the commit in the log.

• Alice chooses to squash (flatten) the last three commits into the first one by editing the first column of those commits as pictured here:

• By pressing ctrl+x plus y, our writer indicates that she is ready to save the list of changes. git shows the comments assigned to the collapsed commits, and Alice replaces them with an explanation of what has happened during all of them:

• Something like “Adding chapter heading to each one” should be good enough to summarize what has happened, so she types it and then presses again ctrl+x plus y.

• The new log entry is much more interesting, as it explains what has happened without providing irrelevant details

git log --oneline --graph

• Now everything is ready to be merged

git checkout main
git merge feat_headings