# 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 functionsfunction usage(    e1, e2){    e1 = "usage: cut [-f list] [-d c] [-s] [files...]"    e2 = "usage: cut [-c list] [files...]"    print e1 > "/dev/stderr"    print e2 > "/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("Using first character of %s" \                " for delimiter\n", Optarg) > "/dev/stderr"                Optarg = substr(Optarg, 1, 1)            }            FS = Optarg            OFS = FS            if (FS == " ")    # defeat awk semantics                FS = "[ ]"        } else if (c == "s")            suppress++        else            usage()    }    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("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, 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("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 ""}