You can fetch all branches from all remotes like this:

git fetch --all

It's basically a power move.

fetch updates local copies of remote branches so this is always safe for your local branches BUT :

  1. fetch will not update local branches (which track remote branches); if you want to update your local branches you still need to pull every branch.

  2. fetch will not create local branches (which track remote branches), you have to do this manually. If you want to list all remote branches: git branch -a

To update local branches which track remote branches:

git pull --all

However, this can be still insufficient. It will work only for your local branches which track remote branches. To track all remote branches execute this oneliner BEFORE git pull --all:

git branch -r | grep -v '\->' | while read remote; do git branch --track "${remote#origin/}" "$remote"; done

TL;DR version

git branch -r | grep -v '\->' | while read remote; do git branch --track "${remote#origin/}" "$remote"; done
git fetch --all
git pull --all

(It seems that pull fetches all branches from all remotes, but I always fetch first just to be sure.)

Run the first command only if there are remote branches on the server that aren't tracked by your local branches.

P.S. AFAIK git fetch --all and git remote update are equivalent.

Kamil Szot's comment, which folks have found useful.

I had to use:

for remote in `git branch -r`; do git branch --track ${remote#origin/} $remote; done

because your code created local branches named origin/branchname and I was getting "refname 'origin/branchname' is ambiguous whenever I referred to it.