Git: How to squash all commits on branch

Question

I make new branch from master with:

git checkout -b testbranch

I make 20 commits into it.

Now I want to squash those

Answer 1

Another solution would be to save all commit logs to a file

git log > branch.log

Now branch.log will have all commit ids since beginning.. scroll down and take the first commit (this will be difficult in terminal) using the first commit

git reset --soft

all commits will be squashed