How to implement simple shell, unix programming sandbox

Another snippet from Unix Sandbox. Do You want to write Your own shell? Maybe fork this code and improve it. Here is only basic concept. The main thing to improve is tokenizer for arguments. Adding history of commands is also a good idea.

What's done?
- CTRL+Z sigaction exit
- Main flow of fork and exec*
- Some hardcore tokenizer for 4 arguments (+ command)


But be aware, it's only for fun :)

666:>ls -l
-rw-r--r-- 1 root root 12315 lut 15 17:53 CMakeCache.txt
drwxr-xr-x 5 root root  4096 lut 15 18:10 CMakeFiles
-rw-r--r-- 1 root root  1433 lut 13 08:25 cmake_install.cmake
-rw-r--r-- 1 root root    80 lut 15 17:54 cmdhist
-rw-r--r-- 1 root root  5084 lut 15 17:53 Makefile
-rwxr-xr-x 1 root root 18194 lut 15 18:10 shell_terminal
-rw-r--r-- 1 root root  5458 lut 15 17:53 shell_terminal.cbp
666:>pwd
/root/.CLion12/system/cmake/generated/90867f26/90867f26/Debug
666:>asd
sHELL unknown command
666:>

If You don't know how to start check it out:
https://github.com/khipis/c-unix-sandbox/blob/master/shell-terminal/shell.c