# getopt.awk --- Do C library getopt(3) function in awk
#
# Arnold Robbins, [email protected], Public Domain
#
# Initial version: March, 1991
# Revised: May, 1993

# External variables:
# Optind -- index in ARGV of first nonoption argument
# Optarg -- string value of argument to current option
# Opterr -- if nonzero, print our own diagnostic
# Optopt -- current option letter

# Returns:
# -1 at end of options
# "?" for unrecognized option
# <c> a character representing the current option

# Private Data:
# _opti -- index in multi-flag option, e.g., -abc
function getopt(argc, argv, options, thisopt, i)
{
if (length(options) == 0) # no options given
return -1

if (argv[Optind] == "--") { # all done
Optind++
_opti = 0
return -1
} else if (argv[Optind] !~ /^-[^:[:space:]]/) {
_opti = 0
return -1
}
if (_opti == 0)
_opti = 2
thisopt = substr(argv[Optind], _opti, 1)
Optopt = thisopt
i = index(options, thisopt)
if (i == 0) {
if (Opterr)
printf("%c -- invalid option\n",
thisopt) > "/dev/stderr"
if (_opti >= length(argv[Optind])) {
Optind++
_opti = 0
} else
_opti++
return "?"
}
if (substr(options, i + 1, 1) == ":") {
# get option argument
if (length(substr(argv[Optind], _opti + 1)) > 0)
Optarg = substr(argv[Optind], _opti + 1)
else
Optarg = argv[++Optind]
_opti = 0
} else
Optarg = ""
if (_opti == 0 || _opti >= length(argv[Optind])) {
Optind++
_opti = 0
} else
_opti++
return thisopt
}
BEGIN {
Opterr = 1 # default is to diagnose
Optind = 1 # skip ARGV[0]

# test program
if (_getopt_test) {
while ((_go_c = getopt(ARGC, ARGV, "ab:cd")) != -1)
printf("c = <%c>, optarg = <%s>\n",
_go_c, Optarg)
printf("non-option arguments:\n")
for (; Optind < ARGC; Optind++)
printf("\tARGV[%d] = <%s>\n",
Optind, ARGV[Optind])
}
}