How to download files to sd card from ftp without rooting Simple question, but I couldn t find the answer anywhere (all answers requires rooting on android marshmallow because ftp clients doesn t include the permission to write on the sdcard).
I have a huge file which is too large to be downloaded on internal storage. So it can only be downloaded on the sdcard directly.
It also seems no ternal apps have the permission to write to the sdcard so I cannot use command line tools directly.

As the file is huge, I also need to be able to pause and resume downloads.
I use Folder Sync.
But it depends on your android version,    If you have 5.1 or above then the application developers must include Environment.getExternalStorage.....

EXAMPLE FILE USAGE

File file = new File(Environment.getExternalStorageDirectory(), "myfile.txt"); 


instead of the old hard coded way.

File file = new File("SDCard", "myfile.txt"); 


For more information about pause resume with FTP, i have included a link to a development question regarding pause resume on Android Clients

Folder Sync Free

Developing FTP Client with Pause Resume on Android

For terminal emulator, you should run 

getprop vold.path.external_sd


then try running the external directory as returned   

NOT

sdcard/download/txt.txt


RATHER

storage/sdcard0/download/txt.txt


It's usually just one directory / legacy directory isn't accessible anymore. so you need to get the actual path with some command...

getprop  


getprop will return all current system properties, this includes storage paths and network status results