How to translate a non sugary syntactic shell (Bash) command into "lower" types of code such as assembly or even machine code?

Question

Please consider:

cd ~
cd $HOME

I would say that the first command is a possible sugar syntax of the second command, and that the second is less abstract.

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Just for the sake of demonstrating how commands can become less and less abstract to newcomers to programming (in the context of explaining what is abstraction), focusing on shell, I ask:
How to translate a non sugary syntactic shell (Bash) command into "lower" types of code such as assembly or even machine code (or to anything coming between, say cd $HOME to its assembly representation)?
What software I could use, perhaps in shell, to achieve this goal to demonstrate how a computer command goes from the simple to the complicated?

Answer 1

Since you mention Bash, translating cd into assembly language can be done as follows:

git://git.savannah.gnu.org/bash.git
cd bash
./configure
make
cd builtins
./mkbuiltins -D . cd.def
gcc -S -DHAVE_CONFIG_H -DSHELL  -I. -I..  -I.. -I../include -I../lib -I.    -g -O2 -Wno-parentheses -Wno-format-security cd.c

You’ll then find the corresponding assembly language in builtins/cd.s. (You’ll need a number of development tools installed; how to do that depends on your distribution, and ./configure will tell you what’s missing.)

I doubt this will be very useful, especially for newcomers to programming.

Answer 2

To execute high level shell commands, you need a complex program, the shell.

No amount of assembly or machine code will change the current directory of a process, unless it is the sequence of instructions that calls the kernel. The kernel is even more complex software than the shell, and there is nothing simple about the execution of the chdir, there are again layers of filesystem abstraction.

In general, there is little to gain from assembly or machine code, especially for newcomers to programming.