Has your network administrator blocked the command line shell on your network? Are you looking for an open-source shell that you can compile and run on a multitude of systems? Then Portable Shell may be the solution you're looking for!
Portable Shell (psh) is a simple command-line shell that is intended to replace your system's default shell (cmd for Windows or Bash for *nix) when it is unavailable. psh runs on top of your system shell and passes commands to it without executing it, taking advantage of a simple "loophole." We call this technique Shell-on-shell, or SoS for short.
psh is written in standard Fortran, and designed to compile with gfortran in its standard configuration. This makes it possible to run psh unmodified on a number of platforms.
Well, they blocked Command Prompt on all of the Windows machines at school. Programmers are always command-line junkies, so all of us wanted a new shell.