It seems that this the intended behavior and it's already documented on the man page:
> QUILT_PAGER > The pager quilt shall use for commands which produce paginated > output. > If unset, the values of GIT_PAGER or PAGER is used. If none of > these > variables is set, "less -R" is used. An empty value indicates that > no > pager should be used. `export QUILT_PATCHES=debian/patches; QUILT_PAGER=more quilt series` works. As does: `QUILT_PAGER="" quilt series # no pager` This is the default behavior. You need to either set up a quiltrc inside the chroot or set and export whatever environment variables you're going to need for the session. The fallback `less -R` is needed because `quilt series` has the option to print output in colors, and the -R flag enables that. I don't think changing the fallback value for such corner cases is warranted. However, a bit more informative message is perhaps necessary.
