ormaaj 1712897986 learn c := `[ exec | command | builtin ] c`, command substitution := ( `$(c)` | `${ c; }` | `${| c; }` ), pipeline := `c | c`, asynchronous subshell := ( `c &` | `<(c)` | `>(c)` | `coproc [ name ] { c }` (bash) | `c |&` (ksh) ). `eval` and `source` evaluate shell code. Some less important builtins can too (mapfile, complete, compgen). Baciticks are deprecated.