smsh

README

a Smol shell

(Or, "Shaking my shell head".)

smsh is a small shell based almost entirely on Bash syntax, built in Go and made for ultraportability and simplicity.

smsh is designed to take a list of strings as arguments and treat them as a series of statements. This makes it easy to use the string array of the exec syscall to clearly send a series of statements without more parsing, e.g. ["bash", "-c", "stmt1; stmt2; stmt3"] is equivalent to ["smsh", "--", "stmt1", "stmt2", "stmt3"]. The utility of this kind of composition probably makes sense to you especially if you've used something like dockerfiles (it's a lot clearer to append array elements than it is to concatenate strings to the last element of an array and hope that the result is not only syntactically valid but semantically correct). Each individual statement string does not need escaping with smsh; with bash, to be safe, it would (though usually people simply ignore this).

smsh will keep a short record of the string of each command it runs, and time each command, and can print this out in a table at the end of the whole smsh invocation. This is sort of like Bash's set -x mode plus wrapping each command with time, then prettyprinting the final result. (We print this at the end of the whole smsh invocation rather than at each command launch because this remains usable even if some of your commands produce more-than-the-scrollback-limit amounts of output.) This information can be printed in a human-friendly textual table, or in json, and can be sent to a file descriptor of your choice for mechanical parsing.

smsh will default to exit-on-error, unlike bash, which by default ignores exit codes. This is similar to Bash set -e mode. (See http://redsymbol.net/articles/unofficial-bash-strict-mode/ for a discussion of why exit-on-error is sane.) If there are commands you explicitly want to ignore the failure of, you can use the cmd || true pattern.

Acknowledgements

smsh uses the shell parser https://github.com/mvdan/sh , which is a spectacular piece of work and without which smsh could not exist.