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On Thu, 2 Feb 2006, Joe Pluta wrote:
Forgive me Marty as I root around in my brain for old data. IIRC, Unix OS's can run multiple shells (C shell, Bourne, bash, Korn) and each shell is different. The syntax differences between these shells are pretty radical. And then different flavors of Unix have different commands; not all Unix variants share the same names for all utilities.
You are correct. There are good and bad sides to this. The bad side is that the differences mean that programming syntax you learned in one shell may not apply to another shell. The good side is that there is a shell to suit almost every taste and you can find something you really enjoy working on. Keep in mind that the differences are really only apparent when programming with the shell, just using the command line is the same across all shells.
Another thing about shells is that several are simply improvements on older versions. For example tcsh is an improved csh (C shell) and bash is an improved Bourne shell (bash stands for Bourne-Again SHell - gotta love it).
Another good point you make is that commands differ somewhat between different unix vendors. It can be quite frustrating to suddenly find that your favorite command doesn't have the same options when you switch do a different unix vendor. This problem was addressed by the POSIX standard which attempted to define a set of commands that would work on all versions of unix. These days vendors do a good job of following the POSIX standard and thus the problem is minimized. Even better, all unix vendors I'm familiar with provide the GNU utilities which replace most of the vendor's commands with the GNU versions which in addition to making commands identical across all platforms often perform better as well.
So I guess my point is that QShell is just another shell, and AFAIK the PASE shell is actually much more compliant to other *nixes (I think PASE is a POSIX compliant shell).
Coming back to the iSeries (i5) qshell is quite nice but also somewhat limited. It would be nice if it supported the history command and recall via the !<command number> mechanism. A paginator would also be nice but impossible I fear due to the screen at a time nature of the 5250 protocol. And filename completion with the tab key would be wonderful but impossible for the same reason. But don't take these critisisms as a vote against qshell - I love having it on the box!
btw - if you are interested in more unix history a thorough series of articles exists on Groklaw:
http://www.groklaw.net/staticpages/index.php?page=20051013231901859 James Rich It's not the software that's free; it's you. - billyskank on Groklaw
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