Warning: do not use the following command unless you want to lose uncommitted work!
Using git reset
has been explained, but you asked for an explanation of the piped commands as well, so here goes:
git ls-files -z | xargs -0 rm -f
git diff --name-only --diff-filter=D -z | xargs -0 git rm --cached
The command git ls-files
lists all files git knows about. The option -z
imposes a specific format on them, the format expected by xargs -0
, which then invokes rm -f
on them, which means to remove them without checking for your approval.
In other words, "list all files git knows about and remove your local copy".
Then we get to git diff
, which shows changes between different versions of items git knows about. Those can be changes between different trees, differences between local copies and remote copies, and so on.
As used here, it shows the unstaged changes; the files you have changed but haven't committed yet. The option --name-only
means you want the (full) file names only and --diff-filter=D
means you're interested in deleted files only. (Hey, didn't we just delete a bunch of stuff?)
This then gets piped into the xargs -0
we saw before, which invokes git rm --cached
on them, meaning that they get removed from the cache, while the working tree should be left alone — except that you've just removed all files from your working tree. Now they're removed from your index as well.
In other words, all changes, staged or unstaged, are gone, and your working tree is empty. Have a cry, checkout your files fresh from origin or remote, and redo your work. Curse the sadist who wrote these infernal lines; I have no clue whatsoever why anybody would want to do this.
TL;DR: you just hosed everything; start over and use git reset
from now on.