How to Fix sudo Missing Environment Variables on Linux

Background

When a command is executed with sudo, the environment is reset to a safe default; custom variables disappear unless explicitly preserved.

Configuration File

The sudo configuration resides in /etc/sudoers and requires root privileges to read or edit.

sudo sed '/^#/d;/^$/d' /etc/sudoers

Key Directives

Defaults env_reset (line 3) enables the default environment reset.

Lines 4‑8 contain env_keep entries; variables listed inside double quotes are retained.

Line 9 defines secure_path , which sets the PATH used by sudo. Adding missing command directories here allows sudo to locate them.

Methods to Preserve Variables

Use the -E option: sudo -E command runs the command with the caller’s environment unchanged. This may fail if the user lacks permission for certain variables.

Edit /etc/sudoers to adjust env_keep and secure_path so required variables and paths are retained.

Manually set variables before invoking sudo or create an alias that injects the current PATH , e.g., alias sudo='sudo env PATH=$PATH' . Disabling the reset entirely can be done by changing Defaults env_reset to Defaults !env_reset and handling PATH in .bashrc .

Reference URLs

https://www.google.com

http://ghoulich.xninja.org/2017/05/09/how-to-find-env-variables-when-exec-sudo-commands/

http://www.ibm.com/developerworks/cn/aix/library/au-sudo/index.html