List all virtualenv
You can use the lsvirtualenv, in which you have two options "long" or "brief":
"long" option is the default one, it searches for any hook you may have around this command and executes it, which takes more time.
"brief" just take the virtualenvs names and prints it.
brief usage:
$ lsvirtualenv -b
long usage:
$ lsvirtualenv -l
if you don't have any hooks, or don't even know what i'm talking about, just use "brief".
To list all the virtual environments (if using the anaconda distribution):
conda info --envs
Hope my answer helps someone...