[bash] wanted: function with a clean way for multiple return values
Hi,
I have a small part of a project which is done as a bash script. bash was selected as an portability issue that works out of the box. In this script I have an exec shell-function, a wrapper around arbitrary commands. I want to have STDOUT, as an addon STDERR and the EXIT-CODE of a specified command.
I'd like to have a clean wrapper, but my solution at the moment is ugly and does not produce clean code at the calling side. Maybe you have some hints to improve it.
In saying "clean" I'm thinking of side effect free programming, i. e. don't get into a mess with global variables and encapsulate all within the _exec function and just have that function to be called. (In the current situation, I have to use an additional line for every extra parameter I'm getting from _exec in the calling function.) I'd like to avoid eval("eval" should better be named "evil") too .
That's what I have so far:
Code:
function _dbg {
# verbose logging here
}
function _fatal {
# fatal error handling here
}
function _exec {
local CMD=$1
local OUT="$( $CMD 2>&1 ;echo "||$?" )"
local EXIT_CODE="${OUT##*||}"
# if no output is there at all [[:space:]]* does
# not match. So do one with space and one without
OUT="${OUT%[[:space:]]*||[0-9]*}"
OUT="${OUT%||[0-9]*}"
OUT="${OUT:-<EMPTY>}"
if [ "$EXIT_CODE" != "0" ]; then
_fatal $ESHELLERR "$EXIT_CODE" "$OUT" "$CMD"
else
_dbg "SHELL EXEC successful CMD: $CMD EXIT_CODE: $EXIT_CODE OUT: $OUT"
fi
echo "$EXIT_CODE||$OUT"
}
function _delete_compatible {
local DIR="$1"
local OUT="$(_exec "rm -rf $DIR")"
local EXIT_CODE="${OUT%||*}"
OUT="${OUT#*||}"
if [ "$EXIT_CODE" == "0" ]; then
_dbg "compatible delete successful"
_success
else
echo "$OUT"
fi
}
OpenBSD complains when it sees this function in my program
/*This function takes the string "test\n" and returns the string "test\n\test\ntest\n"
ENTROPY = 1024
*/
void *build_string(int count, char **strarr)
{
int k;
char *new;;
size_t max;
if(count == 0) {
... (2 Replies)
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#include <stdio.h>
void foo(int id, char *first_name, char *last_name)
{
/*
this is just an example to illustrate my problem... real code makes
use of the "id" parameter.
*/
first_name = (char... (8 Replies)
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if then;
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line xxx: [: too many arguments
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# raidctl -l
RAID Volume RAID RAID Disk
Volume Type Status Disk Status
------------------------------------------------------
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Hi,
I need to retrun multiple values
function errorFileCreation
{
echo "Before"
return -1 "Siva";
echo "Aftyer"
}
echo ${?} - This can be used to getting first value.
how can i get second one.
Advance Thanks...
Shiv (3 Replies)
I know multiple values can be returned from a function in C like this:
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Hi
I am pretty confused in returning and capturing multiple values
i have defined a function which should return values "total, difference"
i have used as
#!/usr/bin/ksh
calc()
{
total=$1+$2
echo "$total"
diff=$2-$1
echo "$diff"
}
I have invoked this function as
calc 5 8
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Discussion started by: Priya Amaresh
2 Replies
LEARN ABOUT OPENSOLARIS
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)Linux Epoch Linux
07-12-2016
.