core utils

Implemetations of Unix core utils in C.

Why?

For get new skills in development and reverse engineering. 🙃

Available

• echo
• head
• cat
• true
• false

more in future...

Decisions

echo

Input text must be in quotation marks, e.g.:

echo -n "sample text"

Why? In GNU echo isn't possible to run --version or --help option via a command from PATH because echo returns all arguments to stdout. You must specify full path for it (/bin/echo) to do that.

This implementation allows to run correctly:

echo --help

true & false

These tools don't have any useless additional options. Simply returns only 0 (true) or 1 (false).

cat

Available only -n additional flag for numerate lines. In my opinion other options are useless.

Compilation

GCC

gcc -O3 utility_name.c -o binary_name

Installation

Not recommended. This is only for fun, but if you very want... you can. It should be works ok. 😄

sudo install -Dm755 "binary_name" "/usr/bin/binary_name"