Please tell us what error messages apt-get gave you.
When I attempt to install gvim I get this error message:
'Reading package lists... Done
Building dependency tree
Reading state information... Done
Package gvim is a virtual package provided by:
You should explicitly select one to install.
E: Package 'gvim' has no installation candidate'
The solution is to select the right package from the list given.
When I try to install csh I get this error message if I do not have an internet connection:
'Temporary failure resolving ports.ubuntu.com'
The solution in this case is to connect to internet, usually through WiFi. After connecting to the internet csh installed cleanly.
Full Disclosure: I am an employee of Qualcomm Canada. Any opinions expressed in this or any other post may not reflect the opinions of my employer