addr

#!/bin/sh
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
# Copyright 2014 Jeremy Brubaker <jbru362@gmail.com>
#
# abstract: list bound IP addresses
#
# Documentation {{{1
#
VERSION='1.0'

print_help() (
    [ -n "$1" ] && printf "%s\n" "$1"

    cat <<END
Usage: $0 [OPTION] [INTERFACE]

List bound IP addresses

  -a	    include 127.* addresses
  -l	    prepend address with the interface it is bound to
  -4	    print IPv4 addresses (default)
  -6	    print IPv6 addresses
  -s        sort output
  -h   	    display this help and exit
  -v        output version information and exit
END
) >&2

print_version() (
    cat <<END
$0 $VERSION
Copyright (C) 2014 Orion Arts
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by Jeremy Brubaker.
END
) >&2

# Process options {{{1
#
all='n'
long='n'
sort='n'
v4='y'
v6='n'
while getopts ':alshv46' c; do
    case $c in
        a) all='y' ;;
        l) long='y' ;;
        4) v4='y'; v6='n' ;;
        6) v6='y'; v4='n' ;;
        s) sort='y' ;;
        h) print_help; exit 0 ;;
        v) print_version; exit 0 ;;
        ?) print_help "Invalid option: -$OPTARG";  exit 1 ;;
    esac
done
shift $((OPTIND-1))
OPTIND=1

# Easy way to not ignore 127.* addresses if we ask for such an interface
# explicitly
[ -n "$1" ] && all='y'

# Main {{{1
#
if ! command -v ip >/dev/null 2>/dev/null; then
    printf "ip(8) not found. Exiting\n" >&2
    exit 1
fi

[ "$v4" = 'y' ] && inet="inet"
[ "$v6" = 'y' ] && inet="inet6"

# Not quoting $1 allows ignoring non-existent parameter
# shellcheck disable=SC2086
addrs=$(ip address show $1 | awk ' \
    /^[[:digit:]]+:/ { iface = gensub(":", "", 1, $2) } \
    /'$inet' /       { printf("%s\t%s\t%s\n", iface, \
                           gensub("/.*$", "", 1, $2), \
                           gensub("^[^/]*", "", 1, $2))}')

[ "$all" != 'y' ]  && addrs=$(echo "$addrs" \
    | grep -Ev '\s127')
[ "$long" = 'n' ]  && addrs=$(echo "$addrs" \
    | sed 's@^.*\s\(.*\)\s.*$@\1@')

# Pipe through sort if needed, otherwise tee just passes it on
echo "$addrs" |
    if [ "$sort" = 'y' ]; then sort
    else tee
    fi | column --table