Bash – How to Remove Alias from Current Session

You need to put your aliases in a file that will be read upon start of all sessions.

Your ~/.bashrc file should have the following:

if [ -f ~/.bash_aliases ]; then
    . ~/.bash_aliases
fi

that means if you have a file ~/.bash_aliases file then it will be sourced and all the aliases defined in it will be applied in the session. It is the best practice to save your aliases in ~/.bash_aliases, if you don't have the file you can create it manually. As an alternative you can put your aliases in ~/.bashrc.

Also note that, if you want to permanently save the aliases those are defined only for current session of terminal, you can run:

alias >> ~/.bash_aliases

For ksh:

printf "%s\n" "alias shh='sqlplus hfdora/hfdora@hfd1" >> ~/.kshrc
source ~/.kshrc

For bash:

printf "%s\n" "alias shh='sqlplus hfdora/hfdora@hfd1" >> ~/.bashrc
source ~/.bashrc

For zsh:

printf "%s\n" "alias shh='sqlplus hfdora/hfdora@hfd1" >> ~/.zshrc
source ~/.zshrc

Use source for the instant effect

And as @glennjackman said:

A note to readers: ~/.kshrc is for ksh93. For ksh88, either put your aliases in ~/.profile, or use ~/.kshrc but add this to your ~/.profile:

export ENV=$HOME/.kshrc