Ubuntu file permissions

ll

View file permissions

ll hello.txt

display

-rwxr-xr-x ...

• The first drepresentative of a directory, -indicates that the file, lsymbolic link (soft link)
• The second is whether the owner has read permission, which -means that there is no permission, the same below
• The third is whether the owner has write permission
• The fourth is whether the owner has execution permission
• The fifth place is whether the same group has read permission
• The sixth place is whether the same group has write permission
• The seventh is whether the same group has execution authority
• The eighth digit is whether the others have read permission
• The ninth place is whether others have write permission
• The tenth place is whether others have execution authority

chmod

Add read permission for the file to all users

sudo chmod a+r /usr/local/cuda/include/cudnn.h

chmod command

   [ugao] [[+-=][rwx]...] [,...]
   [ugoa]:档案调用权限分三级:档案拥有者,群组,其他
   u:档案拥有者
   g:群组
   o:其他
   a:全部
   [+-=]:
   +:增加权限;
   -:降低权限;
   =:唯一设定权限
   [rwx]:
   r:可读
   w:可写
   x:可执行

File permissions can be changed by digital method. rwx weights are 421 (binary)

sudo chmod 777 hello.txt

To the owner, the same group and others are rwx permissions