21sh is a shell interpreter which is compliant with the POSIX standard. It is totally coded in C language with very strict limitation of allowed functions from the C-Standard Library. The line editting features and the vim mode are implemented by the help of the Termcaps library knowing that Ncurses library is forbidden. Additionally Lex/Yacc are also forbidden so I had to code the Lexer/Parser from scratch for lexical, syntactic and semantic analysis.
Will be updated soon !