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Full Discussion: [bash] wanted: function with a clean way for multiple return values
Top Forums Shell Programming and Scripting [bash] wanted: function with a clean way for multiple return values Post 302977229 by stomp on Thursday 14th of July 2016 04:31:30 PM
Old 07-14-2016
Quote:
OK, some "theory of programming 101" seems to be in order.
Thanks for you effort to help me. I'm not a programmer, but a senior system administrator with experience in a dozen different scripting languages and some mainly school-only experience with C/C++/Java. I read your thread in full but did not discover any additional knowledge, which I do not already have. But again, thanks for your kindness to write such extensive explanations for me.

Quote:
pattern is a filename matching pattern; not a regular expression. To get rid of the last || followed by any string of characters from the end of the variable var , you just need:

Code:
Code:
output=${out%||*}

Of course that is correct. I wrote ${out%||[0-9]*}, because I wanted a numerical value(Exit code) to be matched. That is not meant as a regex. Since it never should be zero chars long, which would be the meaning of the regex. It should be a number followed by something.

The reason was because of the not very likely case, the program output contains ||. I'm realizing now that this is not possible, because ${..%||*} matches only the last occurrance of the the pattern, which must be the one I appended myself. So my construction does not add any extra value.

Code:
OUT="${OUT:-<EMPTY>}"

Quote:
But, I have no idea why that is something you would want to do??? And, if that is something you want to do, that is not the way to do it.
Setting OUT to the string "<EMPTY>" is exactly what I'm accomplishing here. The reason is to explicitly point out in the logfile that the command did not output any result. I want it that way because it's a clearer message than just an empty string, which may have other reasons to occur.

---

Thanks for all hints so far. Any hints on the main question asked? ...which is: Ideas and hints to getting nicer, more easy to use/read bash-code on the calling side outside of the _exec function.
Last edited by stomp; 07-15-2016 at 05:43 PM..
 

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LEARN ABOUT DEBIAN

libbash

LIBBASH(7)							  libbash Manual							LIBBASH(7)

NAME

     libbash -- A bash shared libraries package.

DESCRIPTION

     libbash  is  a package that enables bash dynamic-like shared libraries. Actually its a tool for managing bash scripts whose functions you may
     want to load and use in scripts of your own.

     It contains a 'dynamic loader' for the shared libraries ( ldbash(1)), a configuration tool (ldbashconfig(8)), and some libraries.

     Using ldbash(1) you are able to load loadable bash libraries, such as getopts(1) and hashstash(1).  A bash shared library that can be  loaded
     using
     ldbash(1) must answer 4 requirments:

     1.     It must be installed in $LIBBASH_PREFIX/lib/bash (default is /usr/lib/bash).

     2.     It must contain a line that begins with '#EXPORT='.  That line will contain (after the '=') a list of functions that the library
	    exports.  I.e. all the function that will be usable after loading that library will be listed in that line.

     3.     It must contain a line that begins with '#REQUIRE='.  That line will contain (after the '=') a list of bash libraries that are
	    required for our library.  I.e. every bash library that is in use in our bash library must be listed there.

     4.     The library must be listed (For more information, see ldbashconfig(8)).

   Basic guidelines for writing library of your own:
     1.     Be aware, that your library will be actually sourced. So, basically, it should contain (i.e define) only functions.

     2.     Try to declare all variables intended for internal use as local.

     3.     Global variables and functions that are intended for internal use (i.e are not defined in '#EXPORT=') should begin with:
		  __<library_name>_
	    For example, internal function myfoosort of hashstash library should be named as
		  __hashstash_myfoosort
	    This helps to avoid conflicts in global name space when using libraries that come from different vendors.

     4.     See html manual for full version of this guide.

AUTHORS

     Hai Zaar <haizaar@haizaar.com>
     Gil Ran <ril@ran4.net>

SEE ALSO

     ldbash(1), ldbashconfig(8), getopts(1), hashstash(1) colors(1) messages(1) urlcoding(1) locks(1)

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