Paul Heinen - 2017-10-12

getoptions - analyse all option parameters using a list of patterns

~~~ usage: getoption [<option_list>] <p1> <p2> <p3> ...

option_list: space-separated list of option_patterns to test against the parameter(s)

p1, p3, p3: parameters to examine

reports on STDOUT:

multiline list with identified options: <option> <value> on OK

<remainder_of_a_parm> unnown option(s) (rc=255)

returncodes:

nshift nr of parms handled as options

255 unknown option(s), reported on STDOUT

parameters '-' (read from STDIN) and '--' (end of options) are handled POSIX compliant

option_pattern may require a value, like so: -x: or -x= (numeric value)

<value> is to be found in the current parm field directly after the option string,

or in the next parameter, like so: -p12, or -pABC, or -p:ABC, or -p ABC

a default value may be defined in <option_pattern>, like so: -x:ABC or -x=123

if the default value is numeric, a numeric value is expected

an embedded '*' in option_pattern defines a variable length right hand part

the option is matched if (a) full length of pattern or (b) terminated ( : = or numeric )

an embedded '?' functions likewise, and allows matching the left hand part only

matching examples:

info matches -abcinfoxyz

i*nfo matches -abcinfo, -abcinf, -abcin, -abci; but not -abcimfo

i*nfo= matches -abci:2xyz etc., returns value=2 (the value in the parameter(s))

i*nfo: matches -abci:2xyz etc., returns value=2xyz (the value in the parameter(s))

i?nfo: matches -abcinfoxyz, -abcixyz

-info matches -info, -infoxyz; but not -abcinfo

info=3 matches -abcinfoxyz, returns value=3 (the default value)

option_list may include a '?' pattern (at the end of the list):

this will catch unknown option(s), reported as <?> <remainder_of_parm1>

you are then free to apply your own error handling as required.

an option_pattern ending with '&' will collect all following option parameters

(these should all start with '-' or '--' )

an option_pattern with '~' as value separator will report the default value

option_patterns with '::' or '==' separator will not take a value from the next parm

HOWTO (example)

optlist="list vverbose f*ile:" # define our list of options

r=$(getoptions "$optlist" "$@") # analyse our parameter list

rc="$?" # keep getoptions returncode

[ "$rc" == 255 ] && errexit "unknown option(s) $r" # some incorrect option

shift "$rc" # shift out the parameters which are options

while read opt val; do # read list of <option> <value>

[ -z "$opt" ] && break # protect against empty list $r

... # process $opt and $val # you get all options seen with their values

done <<< "$r" # this feeds the response list into read loop

(c) pmheinen, 2013-2014-2015-2016, paul.heinen@gmail.com