Can't update cabal

Hello all, I’m tring to install a cardano node. I’m using ubuntu 21.04. I’m at the step to type the command “cabal build all”. It return this error:
cabal: Error parsing project file
/home/emanuele/cardano-src/cardano-node/cabal.project:105:
“” (line 2, column 1):
unexpected ‘b’
expecting space or end of input
so i thought was a cabal version problem because i have 3.0.1.0 but 3.4.0.0 is needed. It try update cabal but if i use curl --proto ‘=https’ --tlsv1.2 -sSf https://get-ghcup.haskell.org | sh it return this error:
Warning: /home/emanuele/.ghcup/cache/ghc-8.10.5-x86_64-fedora27-linux.tar.xz:
Warning: Permission denied
0 208M 0 14 0 0 90 0 28d 01h --:–:-- 28d 01h 90
curl: (23) Failure writing output to destination
[ Error ] Download failed: Process “curl” with arguments ["-fL","-o","/home/emanuele/.ghcup/cache/ghc-8.10.5-x86_64-fedora27-linux.tar.xz",“https://downloads.haskell.org/~ghc/8.10.5/ghc-8.10.5-x86_64-fedora27-linux.tar.xz”] failed with exit code 23.
[ Error ] Also check the logs in /home/emanuele/.ghcup/logs
“_eghcup --cache install ghc recommended” failed!
and if i use cabal update it tell me:
Could not deserialize /root.json: Malformed: (line 1, column 1):
unexpected end of input
expecting white space or JSON value

any idea?
tyvm

Which guide are u using?

The cardano developer portal one :slight_smile:
here: Installing cardano-node and cardano-cli from source | Cardano Developer Portal

and has ur user sudo rights?

Try

groups user_name

the output is:
emanuele : emanuele adm cdrom sudo dip plugdev lpadmin lxd sambashare

seems I have the rights?

Yes, it seems the user has sudo rights

I need to fix this trouble. Do you have some advice to give me? Even a forum where I can ask help…

Try to start over and follow this guide