I messed up my zshrc on a remote server and now I can't run any commands!

Question

On a remote machine I changed my zsh settings and it is now broken,
for every keypress it says: "url-quote-magic:1: url-quote-magic: function definition file not found "

I don't have another account on that machine, What can I do to disable the faulty .zshrc so that I can use my shell again and fix it.

Answer 1

You can run a command on the remote server without logging in like this:

ssh -lUSERNAME SERVER COMMAND

e.g.

ssh -lsomeuser someserver 'mv .zshrc .zshrc.bak'

The command given as last argument to ssh will be executed by a non-interactive shell and commands from .zshrc are only executed by interactive shells (see zsh manpage, section on startup and shutdown files).

Answer 2

I could also sftp to the server and overwrite the .zshrc with an empty file or with one that works!

Answer 3

Here, it's easy because the file you've messed up is only used by interactive logins. If you'd messed up ~/.zshenv, or if your login shell was bash and you'd messed up ~/.bashrc (weirdly, bash reads ~/.bashrc if it's a non-interactive login shell and its parent is rshd or sshd), none of the methods that rely on executing a command non-interactively would work.

SSH insists on running a shell. If you have no other way to log in (via another account or via a method other than ssh), then your only recourse is to press Ctrl+C really fast after you're authenticated and before the shell reaches the problematic line. In practice, this can often be done manually; it may help to arrange for the machine to be heavily loaded (CPU or disk). If you have trouble pressing the keys at the right time, try using expect.

Answer 4

I could have changed my shell to bash using:

ssh -luser server 'chsh -s /bin/bash'  

assuming bash is available on the sever and it works for me.

Answer 5

I tried to do a remote edit with vim:

vim sftp://user@server/.zshrc

which didn't work. Although :Nread sftp://server/.zshrc could load the broken .zshrc file and :Nwrite could write it back (I have my public key on the server and ssh without a password).

Still more solutions are very welcome.