How to manually expand a special variable (ex: ~ tilde) in bash

Question

I have a variable in my bash script whose value is something like this:

~/a/b/c

Note that it is unexpanded tilde. When I do ls -lt on this

Answer 1

I believe this is what you're looking for

magic() { # returns unexpanded tilde express on invalid user
    local _safe_path; printf -v _safe_path "%q" "$1"
    eval "ln -sf ${_safe_path#\\} /tmp/realpath.$$"
    readlink /tmp/realpath.$$
    rm -f /tmp/realpath.$$
}

Example usage:

$ magic ~nobody/would/look/here
/var/empty/would/look/here

$ magic ~invalid/this/will/not/expand
~invalid/this/will/not/expand