Question: I want to `su - nginx` so I can check if I have set up soft and hard limit for opened files correctly.

Why can't I `su - nginx`? I get an error `*No passwd entry for user 'nginx'*`

---

**EDIT:**

Of course the user was www-data not nginx...
When I do `su - www-data` I get This account is currently not available.

Basically what my question is, I want to see limits for opened files. If I do `ulimit -n` under root, I get 1024, which I know is wrong...

Answer: 
Nginx is has a system user that have no ability to login, because the shell is /sbin/nologin (or even /bin/false) so you can just SU to it. Uou need to instruct the su command which shell to execute for us.

```
su nginx -s /bin/bash
ulimit -n

```
it looks like that there is no user `nginx` configured on the system.

Check with `cat /etc/passwd | grep nginx`

if you get `This account is currently not available` it means that there is no valid shell configured in `/etc/passwd`. Check [this site](https://geekpeek.net/this-account-is-currently-not-available-login-problems/) on instructions how to fix it.