$ sudo apt update

Get:1 http://security.ubuntu.com/ubuntu bionic-security InRelease [88.7 kB]
Hit:2 http://ppa.launchpad.net/apandada1/brightness-controller/ubuntu bionic InRelease
Ign:3 http://ppa.launchpad.net/blahota/texstudio/ubuntu bionic InRelease
Hit:4 http://ppa.launchpad.net/deadsnakes/ppa/ubuntu bionic InRelease
Hit:5 http://ppa.launchpad.net/indicator-brightness/ppa/ubuntu bionic InRelease
Ign:6 http://ppa.launchpad.net/linaro-maintainers/toolchain/ubuntu bionic InRelease
Hit:7 http://ppa.launchpad.net/pbek/qownnotes/ubuntu bionic InRelease
Hit:8 http://ppa.launchpad.net/ultradvorka/ppa/ubuntu bionic InRelease
Err:9 http://ppa.launchpad.net/blahota/texstudio/ubuntu bionic Release
  404  Not Found [IP: 91.189.95.83 80]
Err:10 http://ppa.launchpad.net/linaro-maintainers/toolchain/ubuntu bionic Release
  404  Not Found [IP: 91.189.95.83 80]
Ign:11 https://dl.bintray.com/sbt/debian  InRelease
Get:12 https://dl.bintray.com/sbt/debian  Release [815 B]
Hit:13 http://us.archive.ubuntu.com/ubuntu bionic InRelease
Get:14 http://us.archive.ubuntu.com/ubuntu bionic-updates InRelease [88.7 kB]
Get:15 http://us.archive.ubuntu.com/ubuntu bionic-backports InRelease [74.6 kB]
Get:16 http://security.ubuntu.com/ubuntu bionic-security/main amd64 DEP-11 Metadata [24.1 kB]
Get:17 http://security.ubuntu.com/ubuntu bionic-security/main DEP-11 48x48 Icons [10.4 kB]
Get:18 http://security.ubuntu.com/ubuntu bionic-security/main DEP-11 64x64 Icons [31.7 kB]
Get:19 http://security.ubuntu.com/ubuntu bionic-security/universe amd64 DEP-11 Metadata [41.3 kB]
Get:20 http://security.ubuntu.com/ubuntu bionic-security/universe DEP-11 48x48 Icons [16.4 kB]
Get:21 http://security.ubuntu.com/ubuntu bionic-security/universe DEP-11 64x64 Icons [105 kB]
Get:22 http://security.ubuntu.com/ubuntu bionic-security/multiverse amd64 DEP-11 Metadata [2,464 B]
Get:24 http://us.archive.ubuntu.com/ubuntu bionic-updates/main amd64 DEP-11 Metadata [284 kB]
Get:25 http://us.archive.ubuntu.com/ubuntu bionic-updates/main DEP-11 48x48 Icons [66.7 kB]
Get:26 http://us.archive.ubuntu.com/ubuntu bionic-updates/main DEP-11 64x64 Icons [134 kB]
Get:27 http://us.archive.ubuntu.com/ubuntu bionic-updates/universe amd64 DEP-11 Metadata [250 kB]
Get:28 http://us.archive.ubuntu.com/ubuntu bionic-updates/universe DEP-11 48x48 Icons [201 kB]
Get:29 http://us.archive.ubuntu.com/ubuntu bionic-updates/universe DEP-11 64x64 Icons [421 kB]
Get:30 http://us.archive.ubuntu.com/ubuntu bionic-updates/multiverse amd64 DEP-11 Metadata [2,468 B]
Get:31 http://us.archive.ubuntu.com/ubuntu bionic-backports/universe amd64 DEP-11 Metadata [7,224 B]
Get:32 http://apt.typesafe.com unicorn InRelease [7,185 B]
Err:32 http://apt.typesafe.com unicorn InRelease
  The following signatures were invalid: D2E3915347209000FA1C06D47CF8D72BE29DF322
Reading package lists... Done
E: The repository 'http://ppa.launchpad.net/blahota/texstudio/ubuntu bionic Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http://ppa.launchpad.net/linaro-maintainers/toolchain/ubuntu bionic Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: GPG error: http://apt.typesafe.com unicorn InRelease: The following signatures were invalid: D2E3915347209000FA1C06D47CF8D72BE29DF322
E: The repository 'http://apt.typesafe.com unicorn InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.