How to Run ‘sudo’ Command Without Entering a Password in Linux

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Aaron Kili

Aaron Kili is a Linux and F.O.S.S enthusiast, an upcoming Linux SysAdmin, web developer, and currently a content creator for TecMint who loves working with computers and strongly believes in sharing knowledge.

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10 Responses

  1. Hubo says:

    Hi,When I opened the sudo.conf, I find a default record, “root ALL=(ALL:ALL) ALL“, my question is what’s the meaning of the third ALL, Thanks.

    • Aaron Kili says:


      The third ALL refers to effective groups, in this line, it means user root can run commands as all groups.

      • Hubo says:

        Follow my understanding, the syntax to add a record is ” =( [, …]:[ ,…]) “, is it right, Thanks.

        • Hubo says:

          Sorry, some mistakes have occured, the syntax to add a record , for example, “root ALL=(user1, user2: group1, group2) NOPASSWD: ALL”, is it right, Thanks.

          • Aaron Kili says:


            Yap, according to the sudoers man page, which explains that, “Multiple users and groups may be present in a Runas_Spec(run as user or group), in which case the user may select any combination of users and groups.

            In this example:

            aaronkilik ALL = (root, bin : operator, system) ALL

            The user aaronkilik may run any command as either user root or bin, optionally setting the group to operator or system. ”

            For additional info, go through the sudoers man page:
            man sudoers

  2. Graeme Moffat says:

    I used '' around ‘username’, which was stripped out.

    That should be –
    Defaults:username !authenticate

  3. Graeme Moffat says:

    You can also add:
    Defaults: !authenticate

  4. BasketCase says:

    Instead of configuring sudo to not require authentication at all you can setup pam_ssh_agent_auth to have it authenticate you by your ssh key.

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