Different Levels of SUDO Access.

As a root user, visudo and insert the following based on your requirement.

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# APPLMGRSU users can su to applmgr

User_Alias  APPLMGRSU = user1

APPLMGRSU ALL = NOPASSWD: /bin/su - applmgr

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# ORACLESU users can su to oracle

User_Alias  ORACLESU = user1

ORACLESU ALL = NOPASSWD: /bin/su - oracle

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# allow the user to issue commands as root without a password

user1 ALL=(root) NOPASSWD: ALL

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#Append the following entry to run ALL command without a password for a user named user1:

user1 ALL=(ALL) NOPASSWD:ALL