"apug" seems to have dissappeared from my Elive beta 64 v 3.8.13. Terminal reports $ 'command not found'. However the full command sudo apt-get update or upgrade are functioning.
That would suggest that "alias" has gone or you're using a different shell than expected.
Check what you've got available with
"alias|grep apt" ... if "api" (or others) isn't there ... you've got an issue.
I changed the theme of zsh, could that be the problem?
Yes, you probably overwrote the path to the aliases doing that.
No worry ... just roll your own by adding the following lines to your ~/.zshrc (they can be found in your ~/.bashrc BTW):
# some useful apt/dpkg aliases
alias aps="apt-get source"
alias apse="apt-cache search"
alias apsh="apt-cache show"
alias appo="apt-cache policy"
alias apu="sudo apt-get update"
alias apug="sudo apt-get update ; sudo apt-get upgrade"
alias api="sudo apt-get install"
alias apui="sudo apt-get update ; sudo apt-get install"
alias apif="sudo apt-get -f install"
alias apr="sudo apt-get remove"
sudo apt-get update
for package in "$@" ; do sudo rm -f /var/cache/apt/archives/"$package"_*.deb ; done
sudo apt-get install --reinstall "$@"
alias apfs="apt-file search"
alias dpi="sudo dpkg -i"
alias dpl="dpkg -l"
alias dpL="dpkg -L"
After which you'll have those apt related aliases available again.
Also learnt something about shell scripting