1: if your computer environment is windows x64, you can download the NuSMV-2.6.0-win64.zip directly.
2: if not, you can also explore the website of NuSMV (http://nusmv.fbk.eu/NuSMV/download/getting-v2.html), in this page you can click Pre-compiled version of NuSMV.
And then, you need enter the check word and click Do not Register.
Finally, you can download the correct version for you computer environment!
In command line, you can enter the NuSMV catalog and then input: NuSMV -int
After that, you should input the following command:
read_model -i "your smv file path"
go
check_ctlspec