openwrt安装软件提示[Errno 28] No space left on device

openwrt路由器安装软件时提示：
ERROR: Could not install packages due to an EnvironmentError: [No space left on device

使用如下命令指定TMPDIR即可：

TMPDIR=/mnt/sdc1   pip install lxml

TMPDIR=/mnt/sdc1为一个比较大的存储空间

可添加额外的参数，如：

TMPDIR=/folder/address/here/ pip install --upgrade --cache-dir=/folder/address/here/ --build /folder/address/here/ tensorflow