Creating permanent-alias bash command - linux

Question

I am trying to create a "permalias" bash command to be able to easily create permanent aliases without having to directly work on the ~/.bashrc file.
As of now, the only way I've been able to make this work is with this code:
alias permalias="echo alias $1 >> ~/.bashrc"
which allows for an input in this format:
permalias commandname=\"commandbody\"
But I am not satisfied with this because I'd like to mantain a simpler input format, one closer to the original alias command's.
I tried several variants of this code:
alias permalias="echo alias $1=\"$2\" >> ~/.bashrc"
Using this version, this code permalias c "echo test" should add this line alias permalias c="echo test" to the ~/.bashrc file.
But instead this is the result: alias c "echo test", which, of course, does not work.
I'd also be grateful for any advice on how to avoid the need of putting the " around the new command's body.
Thank you

Answer 1

Try this:
#!/bin/bash
permalias()
{
local alias_regex='[A-Za-z_0-9]*'
if
[[ $# = 1 && $1 =~ ($alias_regex)=(.*) ]]
then
printf "%s\n" "${BASH_REMATCH[1]}=\"${BASH_REMATCH[2]}\"" >> ~/.bashrc
else
echo "USAGE: permalias VARNAME=ALIAS_COMMAND"
return 1
fi
}
A nicer version would check for the presence of said alias in .bashrc first, and would then replace it or fail if it is already present.

Answer 2

You can't use arguments in an alias. What you need is a function, something like:
permalias() {
echo "alias ${1}=\"${2}\"" >> ~/.bashrc
}

Answer 3

Make it a function as Olli says, then you could use "$*" to concatenate all the arguments to the function.
permalias() {
n=$1;
shift;
echo "alias $n=\"$*\"" >> ~/.bashrc;
}
This should work with stuff like permalias c echo foo bar, but if you actually want quotes inside the alias, it will get hairy. permalias c echo "foo bar" would not work, you'd need something like permalias c echo "'foo bar'" to counter the additional level of command line processing and get the inside quotes to the file.
For anything complicated, it's better to make a shell function anyway. You can use declare -fp funcname to print the definition of a function, and save it to a file if you like.

Answer 4

If you happen to use zsh, drawing on Fred's answer, we can switch $BASH-REMATCH for $match and send the aliases to .zsh_aliases (assuming you have them set up-- if not add .zsh_aliases to your homedir and add this to your .zshrc: source ~/.zsh_aliases).
So, as an example, I added this function to my .zsh_aliases file and it works well.
permalias() {
sauce="unhash -ma "*" ; unhash -mf "*"; source ~/.zshrc"
local alias_regex='[A-Za-z_0-9]*'
if
[[ $# == 1 && $1 =~ ($alias_regex)=(.*) ]]
then
printf "%s\n" "alias ${match[1]}=\"${match[2]}\"" >>~/.zsh_aliases
#uncomment the following line to automatically load your new alias
#eval ${sauce}
else
echo "Usage: permalias ALIAS_NAME=ALIAS_COMMAND"
return 1
fi
}