输入：

./digits-devserver后出现下面的提示：

___ ___ ___ ___ _____ ___
| \_ _/ __|_ _|_ _/ __|
| |) | | (_ || | | | \__ \
|___/___\___|___| |_| |___/ 5.1-dev


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：https://github.com/NVIDIA/DIGITS/issues/1107

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 # Check the new envvar value

#检查新配置
$ $CAFFE_ROOT
/home/username/caffe/

按上面的方法改了之后，digits顺利启动。