Linux Basics

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Permissions - setting setuid

You can make a program setuid by giving 's' instead of 'x' permission. If you have written a script, an example would be:

chmod +s
  1. Start creating file with the name in /tmp directory:

    nano /tmp/whoownsit_$

    Note: If your user name is sandeep1234, the filename would be

  2. Put the following content in the editor in the previous step:

  3. Save it by pressing Ctrl+x and press "y"

  4. Give it setuid permission:

    chmod +sx /tmp/whoownsit_$
  5. Check if you have given correct permission by

    ls -l /tmp/whoownsit_$

It should display something like this in permissions: rwsrwsr_x

Note: Setuid doesn't work in shell sctipts. Please see