how to fetch in git code example

Example 1: git fetch all remote branch

# track all remote branches:
git branch -r | grep -v '\->' | while read remote; do git branch --track "${remote#origin/}" "$remote"; done
# update all local copies of remote branches
git fetch --all
# update all local tracking branches
git pull --all

Example 2: what does git fetch do

The git fetch command downloads commits, files, and refs from a
remote repository into your local repo. Fetching is what you do
when you want to see what everybody else has been working on.
... When downloading content from a remote repo,
git pull and git fetch commands are available to accomplish
the task.