For Knox , you have to make 2 curl calls. The second curl call should be made to the "Location" header obtained from the 1st curl call response.
1st curl call
curl -i -k -u admin:admin-password -X GET 'https://localhost:8443/gateway/default/webhdfs/v1/tmp/uname.txt?op=OPEN' HTTP/1.1 307 Temporary Redirect Date: Tue, 27 Nov 2018 16:21:44 GMT Set-Cookie: JSESSIONID=1219u2f8zreb11eu9fuxlggxhq;Path=/gateway/default;Secure;HttpOnly Expires: Thu, 01 Jan 1970 00:00:00 GMT Set-Cookie: rememberMe=deleteMe; Path=/gateway/default; Max-Age=0; Expires=Mon, 26-Nov-2018 16:21:44 GMT Cache-Control: no-cache Expires: Tue, 27 Nov 2018 16:21:44 GMT Date: Tue, 27 Nov 2018 16:21:44 GMT Pragma: no-cache Expires: Tue, 27 Nov 2018 16:21:44 GMT Date: Tue, 27 Nov 2018 16:21:44 GMT Pragma: no-cache X-FRAME-OPTIONS: SAMEORIGIN Location: https://hadoop1:8443/gateway/default/webhdfs/data/v1/webhdfs/v1/tmp/uname.txt?_=AAAACAAAABAAAACgLvtILkFAljr5PIP7MVSOAump8j0kSwFCPdGCP2R_b1tCZ0V2KGOQuiRiI4_IU7GDG6NqRtK2Vu7DOZeOhbuQUaP1FYtD_-IV3P-VXMbOFbPfbwpNseAuN-RyQduRm5S1mrk0GVbYKQg4NscgsoF0GGsvqKDyPtECwhwkX96E37Jc5_yCnlkw3LVKUY41Hg6LOt96W8-3rTmnrbo7o26dOcpPv1_uv4Q1F18b4yk5N5BNf6HTZdVZ6Q Content-Type: application/octet-stream Server: Jetty(6.1.26.hwx) Content-Length: 0
2nd curl call (url is taken from Location header obtained in 1st curl call)
curl -i -k -u admin:admin-password -X GET https://hadoop1:8443/gateway/default/webhdfs/data/v1/webhdfs/v1/tmp/uname.txt?_=AAAACAAAABAAAACgLvtILkFAljr5PIP7MVSOAump8j0kSwFCPdGCP2R_b1tCZ0V2KGOQuiRiI4_IU7GDG6NqRtK2Vu7DOZeOhbuQUaP1FYtD_-IV3P-VXMbOFbPfbwpNseAuN-RyQduRm5S1mrk0GVbYKQg4NscgsoF0GGsvqKDyPtECwhwkX96E37Jc5_yCnlkw3LVKUY41Hg6LOt96W8-3rTmnrbo7o26dOcpPv1_uv4Q1F18b4yk5N5BNf6HTZdVZ6Q