>Every so often, after a particularly painful bout with interactive Bash, I find myself mentally designing some shell replacement based on some other language,

>Every so often, after a particularly painful bout with interactive Bash, I find myself mentally designing some shell replacement based on some other language, sometimes custom, sometimes something like Python. I would suggest trying Tcl for this use case. I found it to be just the right language with which to replace shell scripts. The syntax and the built-in command set are easily mapped from those of sh (Tcl has "cd"!), however, it has saner and more straightforward semantics than the POSIX shell (like how variable expansion and quoting are handled [1]) as well as more features (e.g, instead of 'set -e' you get real exceptions on errors that you can catch). Tcl also pushes the idea of all values being strings to the point of arguably being homoiconic. A big boon is that external *nix commands are easy to mix with the built-in commands thanks to 'exec' and 'open |command'. For piping external commands 'exec' understands the shell pipeline syntax but generic pipelines can be implemented as well [2]. If you need to ship scripts Jim Tcl, a smaller implementation of the languages, is worth looking into. It is portable and self-contained enough to be used as the basis for a build system [3] and mostly fixes one of Tcl biggest flaws, the lack of closures. Despite the small size it's a real programming language with very reasonable performance and great UTF-8 support, including in regular expressions; I'm making a toy embedded web microframework for it and I was able to get it to service up to 50 requests per second running on an old Palm Pre Plus, which is a pretty slow device. One of the best things about Tcl is eltclsh [4], which allows you to use Tcl as an interactive shell with readline editing and tab completion for commands, variables and filesystem paths. It removes the need to use 'exec' for external commands; when a command is not recognized eltclsh as a procedure or a built-in it looks for it under $PATH. Admittedly, I don't run eltclsh as my login shell but for complex file system manipulation I find it highly useful. Another great feature is that with TclVFS installed and mounted you can 'cd' to FTP paths and copy files from HTTP paths, e.g., cd ftp://www.kernel.org/pub/linux/kernel As for other alternatives to shell suitable for both scripting and interactive use, Racket's XREPL mode could be a candidate if you added path completion to it and maybe ParEdit-like functionality or some kind of autosuggestion for placing parentheses as you type. (I know some people swear by scsh [5] as a shell replacement for scripting but it lacks readline and completion.) [1] http://www.tcl.tk/man/tcl8.5/TclCmd/Tcl.htm http://www.tcl.tk/man/tcl8.5/TclCmd/Tcl.htm [2] http://wiki.tcl.tk/17419 http://wiki.tcl.tk/17419 [3] https://msteveb.github.io/autosetup/ https://msteveb.github.io/autosetup/ [4] https://www.openrobots.org/wiki/eltclsh https://www.openrobots.org/wiki/eltclsh [5] http://scsh.net/ http://scsh.net/