Database Reference
In-Depth Information
Write ( w ) permission : An account has permission to change or
modify the file or folder.
Execute ( x ) permission : An account can enumerate the contents of a
directory. This permission applies to directories only.
To modify the permissions applied to a file, you can use the chmod
command. To add permissions, use the plus ( + ) sign followed by the
appropriate permission letters. For example, to give all users read/write
permissions to the SampleData_4.txt file, you use the following
command:
hadoop dfs -chmod +rw /user/MSBigDataSolutions/
SampleData_4.txt
To remove the permissions, use the minus ( - ) sign:
hadoop dfs -chmod -rw /user/MSBigDataSolutions/
SampleData_4.txt
To control which user the permissions apply to, you can prefix the
permission with u , g , or o , which respectively stand for the user who owns
the file, the group assigned to the file, or all other users. The following
command adds read/write permissions back, but only to the owner of the
file:
hadoop dfs -chmod u+rw /user/MSBigDataSolutions/
SampleData_4.txt
You can modify the owner and group associated with a file or directory by
using chown and chgrp , respectively. To change the owner, you must be
running the command as the super-user account:
hadoop dfs -chown NewOwner /user/MSBigDataSolutions/
SampleData_4.txt
To change the group associated with a file or a directory, you must be either
the current owner or the super user:
hadoop dfs -chgrp NewGroup /user/MSBigDataSolutions/
SampleData_4.txt
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