FM / prog

/usr/share/doc/gawk/examples/prog

Name	Size	Mode	Actions
alarm.awk	2369	0644	edit dl rm
anagram.awk	1358	0644	edit dl rm
awksed.awk	515	0644	edit dl rm
cut.awk	3698	0644	edit dl rm
dupword.awk	507	0644	edit dl rm
egrep.awk	1954	0644	edit dl rm
extract.awk	1883	0644	edit dl rm
guide.awk	165	0644	edit dl rm
histsort.awk	283	0644	edit dl rm
id.awk	1249	0644	edit dl rm
igawk.sh	3189	0644	edit dl rm
indirectcall.awk	1957	0644	edit dl rm
labels.awk	1014	0644	edit dl rm
pi.awk	341	0644	edit dl rm
split.awk	1198	0644	edit dl rm
tee.awk	770	0644	edit dl rm
testbits.awk	736	0644	edit dl rm
translate.awk	1182	0644	edit dl rm
uniq.awk	2700	0644	edit dl rm
wc.awk	1480	0644	edit dl rm
wordfreq.awk	347	0644	edit dl rm

Edit: /usr/share/doc/gawk/examples/prog/cut.awk (3698B)

# cut.awk --- implement cut in awk
#
# Arnold Robbins, arnold@skeeve.com, Public Domain
# May 1993

# Options:
#    -f list     Cut fields
#    -d c        Field delimiter character
#    -c list     Cut characters
#
#    -s          Suppress lines without the delimiter
#
# Requires getopt() and join() library functions

function usage()
{
    print("usage: cut [-f list] [-d c] [-s] [files...]") > "/dev/stderr"
    print("usage: cut [-c list] [files...]") > "/dev/stderr"
    exit 1
}
BEGIN {
    FS = "\t"    # default
    OFS = FS
    while ((c = getopt(ARGC, ARGV, "sf:c:d:")) != -1) {
        if (c == "f") {
            by_fields = 1
            fieldlist = Optarg
        } else if (c == "c") {
            by_chars = 1
            fieldlist = Optarg
            OFS = ""
        } else if (c == "d") {
            if (length(Optarg) > 1) {
                printf("cut: using first character of %s" \
                       " for delimiter\n", Optarg) > "/dev/stderr"
                Optarg = substr(Optarg, 1, 1)
            }
            fs = FS = Optarg
            OFS = FS
            if (FS == " ")    # defeat awk semantics
                FS = "[ ]"
        } else if (c == "s")
            suppress = 1
        else
            usage()
    }

# Clear out options
    for (i = 1; i < Optind; i++)
        ARGV[i] = ""
    if (by_fields && by_chars)
        usage()

if (by_fields == 0 && by_chars == 0)
        by_fields = 1    # default

if (fieldlist == "") {
        print "cut: needs list for -c or -f" > "/dev/stderr"
        exit 1
    }

if (by_fields)
        set_fieldlist()
    else
        set_charlist()
}
function set_fieldlist(        n, m, i, j, k, f, g)
{
    n = split(fieldlist, f, ",")
    j = 1    # index in flist
    for (i = 1; i <= n; i++) {
        if (index(f[i], "-") != 0) { # a range
            m = split(f[i], g, "-")
            if (m != 2 || g[1] >= g[2]) {
                printf("cut: bad field list: %s\n",
                                  f[i]) > "/dev/stderr"
                exit 1
            }
            for (k = g[1]; k <= g[2]; k++)
                flist[j++] = k
        } else
            flist[j++] = f[i]
    }
    nfields = j - 1
}
function set_charlist(    field, i, j, f, g, n, m, t,
                          filler, last, len)
{
    field = 1   # count total fields
    n = split(fieldlist, f, ",")
    j = 1       # index in flist
    for (i = 1; i <= n; i++) {
        if (index(f[i], "-") != 0) { # range
            m = split(f[i], g, "-")
            if (m != 2 || g[1] >= g[2]) {
                printf("cut: bad character list: %s\n",
                               f[i]) > "/dev/stderr"
                exit 1
            }
            len = g[2] - g[1] + 1
            if (g[1] > 1)  # compute length of filler
                filler = g[1] - last - 1
            else
                filler = 0
            if (filler)
                t[field++] = filler
            t[field++] = len  # length of field
            last = g[2]
            flist[j++] = field - 1
        } else {
            if (f[i] > 1)
                filler = f[i] - last - 1
            else
                filler = 0
            if (filler)
                t[field++] = filler
            t[field++] = 1
            last = f[i]
            flist[j++] = field - 1
        }
    }
    FIELDWIDTHS = join(t, 1, field - 1)
    nfields = j - 1
}
{
    if (by_fields && suppress && index($0, fs) == 0)
        next

for (i = 1; i <= nfields; i++) {
        if ($flist[i] != "") {
            printf "%s", $flist[i]
            if (i < nfields && $flist[i+1] != "")
                printf "%s", OFS
        }
    }
    print ""
}

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