Why running command as sudo returns command not found?

Question

Sample command:

drush cc all

works, but this:

sudo drush cc all

gives me:

sudo: drush: command not found

Why? How to fix this?

Answer 1

When you sudo, you get a preconfigured $PATH, which is (supposed to be) something like the root user's default path. Your program is not in that list of directories identified by $PATH.

See for example

• How to make sudo preserve $PATH?
• Why are PATH variables different when running via sudo and su?
• sudoers(5) (see the various settings which relate to PATH)
• sudo(8)

sudo tries to be safe when executing external commands.

There are two distinct ways to deal with environment variables. By default, the env_reset sudoers option is enabled. This causes commands to be executed with a minimal environment containing TERM, PATH, HOME, SHELL, LOGNAME, USER and USERNAME in addition to variables from the invoking process permitted by the env_check and env_keep sudoers options. There is effectively a whitelist for environment variables.

If you cannot configure sudo to preserve your $PATH, the usual workaround is to specify the complete pathname of the program. That may not work well with scripts that call other executables in the (not-accessed) directory.

Answer 2

You should specify the full path. It's also more secure; it you don't specify the path, it's conceivable that an attacker could create another program that will be run with root permissions.

Also, you need to put a line in /etc/sudoers to allow it. man sudoers for the syntax, it's way too much to put here.