The stack ls tools
command will list the tools (principally versions of GHC) that Stack has installed given specified snapshots (if you are using Stack to manage GHC, rather than GHCup) - see ls command - The Haskell Tool Stack.
If that is more versions of GHC than you want, you can delete unwanted ones (the directory and the *.installed
file) from Stack’s programs directory (stack path --programs
).
If you do not want Stack to install versions of GHC ‘automatically’, Stack can be be configured with the install-ghc
option - see Configuration (project and global) - The Haskell Tool Stack.