Shells and the path of standards

It seems that shells evoke almost as much controversy as religion. Everyone has a favorite, and for each favorite, there's another that would sooner grind their knuckles on the back of a circuit board than follow.

As long as I've been using Solaris systems I've never found common ground with the C-shell. Its programming capabilities are more limited compared to other options and its syntax is just too far from standards to be worth learning to me. But C is a standard UNIX language, you say. How can I call C-shell non-standard?

I'm a systems engineer, not an application developer (and now's not the time to debate that grey area!). If I were to write a script to traverse the entire Operating Environment, and calculate a distribution for the various shell I think we'd find 97% written in Bourne shell, 2% written in ksh, and 1% written in Bash. Please remember that I'm talking about Solaris here, and not Linux. When in Rome, do as the Romans do.

Because I create a LOT of shell scripts, I'm also painfully aware of Bourne shell's limitations. Not the least of which is its anemic data structure capability. For that reason, I started to use the Korn shell, or ksh. I have used ksh on Solaris for about 10 years both as my interactive shell and as my programming shell. It's still painful for data structures when compared to Perl, but it's MUCH nicer to work with than the Bourne Subset.

In addition to my Solaris career, I have a life in a parallel universe as a Linux engineer, volunteering at a local not-for-profit organization. There we use Linux for servers because Solaris was too expensive when we chose the initial environment. In the Linux world, the Bourne Again Shell, or Bash, is the de-facto standard for good reason. It's a very capable shell with great programming constructs, and a pleasant demeanor for interactive shell use. I dig it.

In fact, I dug it so much that I recently changed my Solaris interactive shell to it. Bash has been included in Solaris for quite a while now, and I consider it a standard-enough component that it's safe to learn. I love the file completion and history browsing with tab and arrow keys. It's so much more intuitive than the equivalent in ksh. I've been happily bashing around for a few months on Solaris, but recently did an about face in my thinking while reading up on Role Based Access Control, or RBAC.

My current site has a sudo to RBAC conversion on the roadmap, which should be a great project. In the RBAC world, you assume a role to complete an activity that is outside your default privileges. Those roles will have one of three shells: pfcsh, pfsh, or pfksh. Did you notice that Bash is not amongst them? Not for the foreseeable future.

So, in a Solaris-standard world that leverages the powerful RBAC facility, you will not have the option of working in a bash compatible shell if you want to perform an activity outside your normal rights. That's enough reason for me to drop the bells and whistles of Bash and go back to ksh. I'll probably miss it for a few weeks before I forget completely.

This experience proved to be yet another reminder for me that staying on the path of standards is full of temptations. While Bash is stable and common, it is not a native Solaris standard. That's fine for an end-user or software developer that operates outside the OS internals, but as a systems engineer my job is to live in the internals, and at this point in time Korn shell seems to give me the best functionality, programming, and standards compliance.