输入：./digits-devserver后出现下面的提示：
A valid Caffe installation was not found on your system.
Use the envvar CAFFE_ROOT to indicate a valid installation.
Traceback (most recent call last):
File "/usr/lib/python2.7/runpy.py", line 174, in _run_module_as_main
"__main__", fname, loader, pkg_name)
File "/usr/lib/python2.7/runpy.py", line 72, in _run_code
exec code in run_globals
File "/home/zhengguangyuan/digits/digits/__main__.py", line 70, in <module>
main()
File "/home/zhengguangyuan/digits/digits/__main__.py", line 53, in main
import digits.config
File "digits/config/__init__.py", line 7, in <module>
from . import ( # noqa
File "digits/config/caffe.py", line 230, in <module>
executable, version, flavor = load_from_path()
File "digits/config/caffe.py", line 54, in load_from_path
raise ValueError('Caffe executable not found in PATH')
ValueError: Caffe executable not found in PATH
搜到下面页面：
翻译成中文，它的解决方案：
# Check the current value of your envvar
#检查当前envvar的值
$ echo $CAFFE_ROOT
# Add the envvar to ~/.profile so it will load automatically when you login
#把envvar加到~/.profile中，下次当你登录时会自动加载
$ echo "export CAFFE_ROOT=/home/username（我的账户名）/caffe/" >> ~/.profile
# Load the new configuration
#加载新配置
$ source ~/.profile
# Check the new envvar value
#检查新配置
$ echo $CAFFE_ROOT
/home/username/caffe/
按上面的方法改了之后，digits顺利启动。