SHELL

git checkout specific file types only

# BASH (Non-Fish compliant script)
git checkout origin/master -- `git ls-tree origin/master -r --name-only | grep ".pex"`

git checkout specific file types

# You don't need find or sed, you can use wildcards as git understands them (doesn't depend on your shell):
git checkout -- "*.xml"

# The quotes will prevent your shell to expand the command to only files in the current directory before its execution.
# You can also disable shell glob expansion (with bash) :

set -f
git checkout -- *.xml

# This, of course, will irremediably erase your changes!