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: 
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.
If you want to check limit for user `www-data` without editing `/etc/passwd` you can simple run following command:

`su www-data -c 'ulimit -n' -s '/bin/bash'`

```
Options:
  -c, --command COMMAND         pass COMMAND to the invoked shell
  -, -l, --login                make the shell a login shell
  -s, --shell SHELL             use SHELL instead of the default in passwd

```