I tried to run this program (texlive package manager):

```
tlmgr install 

```

and got this error:

```
You don't have permission to change the installation in any way,
specifically, the directory /usr/local/texlive/2012/tlpkg/ is not writable.
Please run this program as administrator, or contact your local admin.

```

So I tried:

```
sudo tlmgr install

```

and got:

```
sudo: tlmgr: command not found

```

Why doesn't sudo find the program? And what can I do about it?