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What's your most useful shell?
Post 302484344 by tetsujin on Thursday 30th of December 2010 03:56:50 PM
12-30-2010
I'm not entirely happy with any of the available options and intend to write my own to rectify the situation. 
I feel there's a huge problem in general with Unix shells, which is the whole problem of encapsulation and delimiters is not adequately addressed. Piping between two processes is easy, but getting it right in the corner cases (i.e. spaces in filenames, etc.) is harder. Most of that difficulty could have been avoided if they had made all the tools support the null character as a delimiter, as GNU find and xargs do. Null is almost universally recognized as something that should not (or, in some cases, can not) appear as a part of a string. But in general I feel that it's important to think about how tools could be made to cooperate better without the need for all this user-directed parsing and re-encapsulation in a pipeline job.
At present I mostly use bash just out of habit. In my search for something better I have looked at mksh and zsh, mostly to see what they have to offer. I like some of the features they offer but still want to come up with something better.
One of my favorite features that I haven't quite found a good use for is ksh coprocesses. It's a little frustrating that the buffer flushing discipline required for coprocs isn't followed by so many of the programs that I might actually want to use as coprocs. It's also a bit annoying that there's just one coproc slot. (You can move the coproc to other file descriptors, but that's another problem with the Unix shell - working with and managing numbered file descriptors is a lousy way to program. They aren't scoped, there's no control over whether they're exported (not that most programs would know what to do with an exported file descriptor anyway), there's nothing to protect you from clobbering one numeric FD with another... At least Bash's named redirection ("command >&{varname}") helps somewhat...
I feel there's a huge problem in general with Unix shells, which is the whole problem of encapsulation and delimiters is not adequately addressed. Piping between two processes is easy, but getting it right in the corner cases (i.e. spaces in filenames, etc.) is harder. Most of that difficulty could have been avoided if they had made all the tools support the null character as a delimiter, as GNU find and xargs do. Null is almost universally recognized as something that should not (or, in some cases, can not) appear as a part of a string. But in general I feel that it's important to think about how tools could be made to cooperate better without the need for all this user-directed parsing and re-encapsulation in a pipeline job.At present I mostly use bash just out of habit. In my search for something better I have looked at mksh and zsh, mostly to see what they have to offer. I like some of the features they offer but still want to come up with something better.
One of my favorite features that I haven't quite found a good use for is ksh coprocesses. It's a little frustrating that the buffer flushing discipline required for coprocs isn't followed by so many of the programs that I might actually want to use as coprocs. It's also a bit annoying that there's just one coproc slot. (You can move the coproc to other file descriptors, but that's another problem with the Unix shell - working with and managing numbered file descriptors is a lousy way to program. They aren't scoped, there's no control over whether they're exported (not that most programs would know what to do with an exported file descriptor anyway), there's nothing to protect you from clobbering one numeric FD with another... At least Bash's named redirection ("command >&{varname}") helps somewhat...
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LEARN ABOUT OPENDARWIN
intro
INTRO(9) BSD Kernel Developer's Manual INTRO(9) NAME
intro -- introduction to system kernel interfaces DESCRIPTION
This section contains information about the interfaces and subroutines in the kernel. PROTOTYPES ANSI-C AND ALL THAT Yes please. We would like all code to be fully prototyped. If your code compiles cleanly with cc -Wall we would feel happy about it. It is important to understand that this isn't a question of just shutting up cc, it is a question about avoiding the things it complains about. To put it bluntly, don't hide the problem by casting and other obfuscating practices, solve the problem. INDENTATION AND STYLE
Believe it or not, there actually exists a guide for indentation and style. It isn't generally applied though. We would appreciate if people would pay attention to it, and at least not violate it blatantly. We don't mind it too badly if you have your own style, but please make sure we can read it too. Please take time to read style(9) for more information. NAMING THINGS
Some general rules exist: 1. If a function is meant as a debugging aid in DDB, it should be enclosed in #ifdef DDB #endif /* DDB */ And the name of the procedure should start with the prefix DDB_ to clearly identify the procedure as a debugger routine. SCOPE OF SYMBOLS
It is important to carefully consider the scope of symbols in the kernel. The default is to make everything static, unless some reason requires the opposite. There are several reasons for this policy, the main one is that the kernel is one monolithic name-space, and pollution is not a good idea here either. For device drivers and other modules that don't add new internal interfaces to the kernel, the entire source should be in one file if possi- ble. That way all symbols can be made static. If for some reason a module is split over multiple source files, then try to split the module along some major fault-line and consider using the number of global symbols as your guide. The fewer the better. SEE ALSO
style(9) HISTORY
The intro section manual page appeared in FreeBSD 2.2. BSD
December 13, 1995 BSD