debian command line keeps adding newline

Sorry if this is an easy one, I've tried searching and it's started to annoy me now. On one of my (Debian) servers the command prompt insists on adding a new line every time. So it looks like this: name@servername ~/directory % how can I get rid if the newline after the directory name, so that I am typing on the same line as name@servername ~/directory and not underneath it. There is no .bashrc file that I can find, and this is the only server that does it. Where else could this be controlled from? --- echo $SHELL:

/bin/zsh

echo $PS1:

%K{blue}%n@%m%k %B%F{cyan}%(4~|...|)%3~%F{white} %# %b%f%k

(probably explains why .bashrc doesn't exist)