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How to Change How Long sudo Waits Before it Prompts You Again

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When you use the sudo command to run commands as root or administrator you are prompted to enter your password. You may have noticed that if you run another command using sudo shortly after the first command, you are not prompted for your password again.

You can customize the length of that grace period in which you are not asked to enter your password for the sudo command again by changing a setting for the sudo command.

NOTE: When we say to type something in this article and there are quotes around the text, DO NOT type the quotes, unless we specify otherwise.

We will open the “/etc/sudoers” file and change a setting to customize the length of the grace period. To begin, press Ctrl + Alt + T to open a Terminal window. Type the following command at the prompt and press Enter.

sudo visudo

Type your password when prompted and press Enter.

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A file opens directly in the Terminal window using the Nano text editor. Use the arrow keys on your keyboard to move the cursor to the end of the following line:

Defaults         env_reset

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IMPORTANT: Never edit the sudoers file with a normal text editor. Always use the visudo command as described here. If the sudoers file has improper syntax, you will be left with a system where it’s impossible to obtain elevated or root privileges. The visudo command opens a text editor like you would with normal text files, but the command also validates the syntax of the file upon saving it. This prevents configuration errors in the sudoers file from blocking sudo operations, and you will lose what could be your only method of obtaining root privileges.

Traditionally, Linux uses vi as the default editor, but Ubuntu has chosen to use Nano. If you would rather use vi as the default text editor in Ubuntu, rather than Nano, see our article.

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Change the line by adding “, timestamp_timeout=x” to the end of the line.

Defaults                 env_reset, timestamp_timeout=x

Replace “x” with the number of minutes you want sudo to wait in the same Terminal session before prompting you to enter your password again.

If you enter “-1” for “x,” the password prompt is revoked. This is not recommended. If you want the system to prompt you for a password every time you use the sudo command, enter “0” for “x.”

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Once you have made the change, press Ctrl + X and type a “y” in response to the question that displays at the bottom of the window to save your changes.

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You will be asked for the File Name to Write at the bottom. Press Enter to accept the default.

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You are returned to the command prompt. To close the Terminal window, type “exit” at the prompt and press Enter. You can also click the X button in the upper-left corner of the window.

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You can also clear the password cache for sudo by typing the following command at the prompt and pressing Enter.

sudo –k

This will cause the password prompt to display again when using sudo even if the entire grace period has not passed.

Lori Kaufman is a freelance technical writer who likes to write geeky how-to articles to help make people's lives easier through the use of technology. She loves watching and reading mysteries and is an avid Doctor Who fan.

  • Published 07/29/14