我在我的 elementaryOS 系统（基于 Ubuntu 18.04）上安装了 texlive-full。每次我尝试使用 tlmgr 安装软件包时，都会出现以下错误。
tlmgr install moderncv
(running on Debian, switching to user mode!)
tlmgr: Remote repository is newer than local (2017 < 2020)
Cross release updates are only supported with
update-tlmgr-latest(.sh/.exe) --update
Please see https://tug.org/texlive/upgrade.html for details.
于是我去获取了 update-tlmgr-latest.sh。当我运行该脚本时，我收到另一条错误消息：
./update-tlmgr-latest.sh
Verifying archive integrity... All good.
Uncompressing TeX Live Manager Updater 100%
./runme.sh: Cannot find TeX Live root using kpsewhich --var-value=SELFAUTOPARENT.
./runme.sh: (no tlpkg/texlive.tlpdb and/or tlpkg/tlpobj/.)
./runme.sh: Please set your PATH as needed, otherwise it's hopeless.
我遗漏了什么
kpsewhich --var-value=SELFAUTOPARENT？/