ccsh - a C++ shell

Rough plan

1. Create a library that implements shell-like syntax and functionality, e.g. ccsh::shell("ls", {"-lah", "--color=auto"}) | ccsh::shell("grep", "rwx")
2. Add ccsh::shell wrappers for coreutils (e.g. ccsh::ls() for ccsh::shell("ls")) (partly done)
3. Pipe this into a C++ interpreter, e.g. cling (https://root.cern.ch/cling), which makes a complete C++ shell.

TODO

• Add a normal README.md

• Add functions to make prompt customization easier, like bash PS1 format codes

• Add command operator<(command, command_line_functor);

• Add command to fd conversion, for using commands as files, see https://www.gnu.org/software/coreutils/manual/coreutils.html#tee-invocation

• Add command operator<(command, int fd); and same for <, >>, >=, >>=

DONE

• Add wildcard selection

• Make shell prompt customizable

• Catch signals in cling to behave like bash

• Change shell prompt from cling to ccsh, use # for root shell

• Add ccsh::source for sourcing commands

• Add a flag to command_base to run command in the dtor.

• Fix output redirection permission issue.

• Improve type safety via boost::filesystem (later std::filesystem) and operator""_p

• Invent a fancy syntax for command switches. Giving them as strings (e.g. ccsh::ls("-lah")) lacks static checking and type safety.

• The same goes for argument pairs like cssh::gcc("...", "-o", "file.o")

• Add operator< for input redirection

• Add operator>= for error redirection

• Add operator>> for output appending

• Add operator>>= for error appending

• Add operator|| and operator&&

• Add command operator>(command, std::vector<std::string>&); and same for <, >>, >=, >>=

• Add command operator>(command, std::string&); and same for <, >>, >=, >>=

• Add command operator>(command, command_raw_functor); and same for <, >=

• Add command operator>(command, command_line_functor); and same for >=