UNIX for Advanced & Expert Users

i want to share some file to some user of my group(there are many users in a perticular group). So how should i do that?And i m not a super user.

Not secure:
1. change protections on you directories/files to allow group read access - use chmod

More secure:
1. copy the file to /var/tmp or /tmp and chmod to allow group/world read access.
2. if you don't want anyone esle to read the file, then leave default protections and then

Code:

chown newuser /var/tmp/filename

but by this entire my group will access it , but i want only some of them to access

Then you have a problem. You can grant access to one user, or to the whole group.
Not just three users in a group.

The second solution above lets one user see the file. Unless the world read or group read is on.

If your filesystem supports access control lists, then you can manipulate the acl to allow only certain users access to the file(s). Most Unix filesystems do not natively support acl's. If your system has acl's then

Code:

man chacl

should show you how to do it.

can we have anything like .rhosts or .ssh/knownhosts ?

The only real solution is to create a new group.