What this line means in oh-my-zsh?

Question

In the oh-my-zsh's upgrade tool, I found this line(line 2):

current_path=${current_path/ /\\ }

What it did?

Additionally, this line works on mac, but on my ubuntu server it output a error says:

.oh-my-zsh/tools/upgrade.sh: 2: .oh-my-zsh/tools/upgrade.sh: Bad substitution

Answer 1

Updated it on Ubuntu with

cd ~/.oh-my-zsh
bash ~/.oh-my-zsh/tools/upgrade.sh