下面的代码可以在Linux上运行，但不能在OSX上运行。

这根本不依赖于DNS，即使/etc/hosts没有正确设置(1是1.0.0.0的简写)，它也能工作:

ip route get 1 | awk '{print $NF;exit}'

或者避免awk，使用谷歌的公共DNS 8.8.8.8。

ip route get 8.8.8.8 | head -1 | cut -d' ' -f8

一种不太可靠的方式:(见下面的评论)

hostname -I | cut -d' ' -f1

如果你知道网络接口(eth0, wlan, tun0等):

ifconfig eth0 | grep addr: | awk '{ print $2 }' | cut -d: -f2

对于linux机器(不是OS X):

hostname --ip-address

我浏览了很多链接(StackExchange, AskUbuntu, StackOverflow等)，并决定将所有最好的解决方案合并到一个shell脚本中。

在我看来，这两个qa是我见过的最好的:

如何在shell脚本中获得我的外部IP地址? https://unix.stackexchange.com/q/22615

我如何找到我的内部ip地址? https://askubuntu.com/a/604691

下面是基于rsp在他的存储库(https://github.com/rsp/scripts/)中分享的一些想法的解决方案。

有些人可能会说这个脚本对于这么简单的任务来说是非常大的，但我想让它在使用时尽可能地简单和灵活。它支持简单的配置文件，允许重新定义默认值。

它在Cygwin, MINGW和Linux (Red Hat)下成功测试。

显示内部IP地址

myip -i

显示外部IP地址

myip -e

源代码，也可通过链接:https://github.com/ildar-shaimordanov/tea-set/blob/master/home/bin/myip。配置文件的示例在那里，在主脚本旁边。

#!/bin/bash

# =========================================================================
#
# Getting both internal and external IP addresses used for outgoing 
# Internet connections.
#
# Internal IP address is the IP address of your computer network interface 
# that would be used to connect to Internet.
#
# External IP address is the IP address that is visible by external 
# servers that you connect to over Internet.
#
# Copyright (C) 2016 Ildar Shaimordanov
#
# =========================================================================

# Details of the actual implementation are based on the following QA:
#
# How can I get my external IP address in a shell script?
# https://unix.stackexchange.com/q/22615
#
# How do I find my internal ip address?
# https://askubuntu.com/a/604691

# =========================================================================

for f in \
    "$( dirname "$0" )/myip.conf" \
    ~/.myip.conf \
    /etc/myip.conf
do
    [ -f "$f" ] && {
        . "$f"
        break
    }
done

# =========================================================================

show_usage() {
    cat - <<HELP
USAGE
  $( basename "$0" ) [OPTIONS]

DESCRIPTION
  Display the internal and external IP addresses

OPTIONS
  -i  Display the internal IP address
  -e  Display the external IP address
  -v  Turn on verbosity
  -h  Print this help and exit
HELP
    exit
}

die() {
    echo "$( basename "$0" ): $@" >&2
    exit 2
}

# =========================================================================

show_internal=""
show_external=""
show_verbose=""

while getopts ":ievh" opt
do
    case "$opt" in
    i )
        show_internal=1
        ;;
    e )
        show_external=1
        ;;
    v )
        show_verbose=1
        ;;
    h )
        show_usage
        ;;
    \? )
        die "Illegal option: $OPTARG"
        ;;
    esac
done

if [ -z "$show_internal" -a -z "$show_external" ]
then
    show_internal=1
    show_external=1
fi

# =========================================================================

# Use Google's public DNS to resolve the internal IP address
[ -n "$TARGETADDR" ] || TARGETADDR="8.8.8.8"

# Query the specific URL to resolve the external IP address
[ -n "$IPURL" ] || IPURL="ipecho.net/plain"

# Define explicitly $IPCMD to gather $IPURL using another tool
[ -n "$IPCMD" ] || {
    if   which curl >/dev/null 2>&1
    then
        IPCMD="curl -s"
    elif which wget >/dev/null 2>&1
    then
        IPCMD="wget -qO -"
    else
        die "Neither curl nor wget installed"
    fi
}

# =========================================================================

resolveip() {
    {
        gethostip -d "$1" && return
        getent ahostsv4 "$1" \
        | grep RAW \
        | awk '{ print $1; exit }' 
    } 2>/dev/null
}

internalip() {
    [ -n "$show_verbose" ] && printf "Internal: "

    case "$( uname | tr '[:upper:]' '[:lower:]' )" in
    cygwin* | mingw* | msys* )
        netstat -rn \
        | grep -w '0.0.0.0' \
        | awk '{ print $4 }'
        return
        ;;
    esac

    local t="$( resolveip "$TARGETADDR" )"
    [ -n "$t" ] || die "Cannot resolve $TARGETADDR"
    ip route get "$t" \
    | awk '{ print $NF; exit }'
}

externalip() {
    [ -n "$show_verbose" ] && printf "External: "

    eval $IPCMD "$IPURL" $IPOPEN
}

# =========================================================================

[ -n "$show_internal" ] && internalip
[ -n "$show_external" ] && externalip

# =========================================================================

# EOF

ifconfig | grep "inet addr:" | grep -v "127.0.0.1" | grep -Eo '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}'  | head -1

假设你需要自己的主要公共IP，就像从世界其他地方看到的那样，尝试以下任何一种:

wget http://ipecho.net/plain -O - -q
curl http://icanhazip.com
curl http://ifconfig.me/ip