%cd magic does not work

[gaow]

Is this the pending PR request will address, or can be fixed without upstream changes?

[BoPeng]

%cd does not change the current directory of a running kernel so it needs to be executed before the kernel is started.

I could not find a way to change current directory of a running process.

[BoPeng]

But when I think of this problem now, I think we can define a command for each kernel and execute it silently to change directory with the %cd magic.

[gaow]

So this is indeed specific to JupyterLab and related to the PR? Because back in SoS notebook:

and I've been relying on this feature to keep my notebook out of the dir with messy output data files.

[BoPeng]

No. If you start a subkernel before you use %cd, %cd does not apply to the subkernel.

This should be the same for JLab and Jupyter Notebook.

[BoPeng]

• sos: os.chdir(os.path.expanduser(to_dir))
• python2/python3: the same
• R: setwd(dir)
• matlab: cd dir
• node/javascript: process.chdir('/tmp');
• bash: cd dir
• SAS: x 'cd <full path>'; (according to here)
• julia: cd("/")

A potential problem is that dir might be given in a format that is not acceptable to some of the kernels.

[BoPeng]

From Jupyter Notebook, not lab

1. cd before kernel starts

2. cd after kernel starts

[BoPeng]

Fixed.