That time has come - a binary tool.

  Added `ipaddr` source code, which is written in C.  It can
 be compiled with `make build`.

Author: skx

.gitignore

@@ -0,0 +1,3 @@
+syntax: glob
+
+ipaddr

Makefile

@@ -17,6 +17,9 @@ nop:
 	@echo "make tidy   - Run the perl code through perltidy."
 	@echo ""
 
+build:
+	gcc -o ipaddr ipaddr.c -Wall -Werror
+
 clean:
 	rm *.bak *~ || true
 

README.md

@@ -104,6 +104,32 @@ Alternatives
 * ..
 
 
+ipaddr
+------
+
+Get IP addresses easily, either all IPs, all those which are IPv4/IPv6, or
+those for a device.  Designed primarily for scripting.
+
+Example:
+
+      $ ./ips -4
+      lo 127.0.0.1
+      eth0 80.68.84.102
+      eth0 80.68.84.104
+
+Or to see all IPv6 addreses on eth0:
+
+      $ ipaddr -6 -d eth0
+      eth0 2001:41c8:10b:102::10
+      eth0 fe80::216:3eff:fe08:16a4
+
+**NOTE** Requires compilation via `make build`.
+
+Alternatives:
+
+* `ip -[46] addr  show`
+* `ifconfig -a`
+
 
 maybe
 -----

ipaddr.c

@@ -0,0 +1,143 @@
+/**
+ * ipaddr - Show the IP addresses associated with given devices.
+ *
+ * Usage:
+ *   ips [options]
+ *
+ * Options:
+ *
+ *   --all    Show all familes.
+ *   --ipv4   Show IPv4.
+ *   --ipv6   Show IPv6.
+ *   --device Show only the given device.
+ *
+ * Examples:
+ *
+ *  $ ips -d eth0 -4
+ *  eth0 192.168.0.3
+ *
+ *  $ ips -a
+ *  lo 127.0.0.1
+ *  eth0 192.168.0.3
+ *  lo ::1
+ *  eth0 fe80::62a4:4cff:fe2d:fab9
+ *  teredo 2001:0:53aa:64c:301f:13f3:4fe4:3a0b
+ *  teredo fe80::ffff:ffff:ffff
+ *
+ */
+
+#include <stdio.h>
+#include <sys/types.h>
+#include <ifaddrs.h>
+#include <netinet/in.h>
+#include <string.h>
+#include <arpa/inet.h>
+#include <stdlib.h>
+#include <getopt.h>
+
+
+int main (int argc, char * argv[])
+{
+    int c;
+
+    /**
+     * Flags.
+     */
+    char *dev = NULL;
+    int show_ipv4 = 0;
+    int show_ipv6 = 0;
+
+    while (1)
+    {
+        static struct option long_options[] =
+            {
+                {"device", required_argument, 0, 'd'},
+                {"all",    no_argument, 0, 'a'},
+                {"ipv4",   no_argument, 0, '4'},
+                {"ipv6",   no_argument, 0, '6'},
+                {0, 0, 0, 0}
+            };
+
+        /* getopt_long stores the option index here. */
+        int option_index = 0;
+
+        c = getopt_long(argc, argv, "d:a46", long_options, &option_index);
+
+        /* Detect the end of the options. */
+        if (c == -1)
+            break;
+
+        switch (c)
+        {
+        case '4':
+            show_ipv4 = 1;
+            break;
+        case '6':
+            show_ipv6 = 1;
+            break;
+        case 'a':
+            show_ipv4 = 1;
+            show_ipv6 = 1;
+            break;
+        case 'd':
+            dev = strdup( optarg );
+            break;
+        case '?':
+            /* getopt_long already printed an error message. */
+            exit(1);
+            break;
+
+        default:
+            fprintf( stderr, "Unknown argument" );
+            exit (1);
+        }
+    }
+
+    struct ifaddrs * ifAddrStruct=NULL;
+    struct ifaddrs * ifa=NULL;
+    void * tmpAddrPtr=NULL;
+
+    getifaddrs(&ifAddrStruct);
+
+    for (ifa = ifAddrStruct; ifa != NULL; ifa = ifa->ifa_next)
+    {
+        /**
+         * If we have a non-null entry.
+         */
+        if ( ifa && ifa->ifa_addr )
+        {
+
+            /**
+             * And it is IPv4 and we're showing IPv4 ..
+             */
+            if (ifa ->ifa_addr->sa_family==AF_INET && show_ipv4 )
+            {
+
+                tmpAddrPtr=&((struct sockaddr_in *)ifa->ifa_addr)->sin_addr;
+                char addressBuffer[INET_ADDRSTRLEN];
+                inet_ntop(AF_INET, tmpAddrPtr, addressBuffer, INET_ADDRSTRLEN);
+
+                if ( ( dev == NULL ) ||
+                     ( strcmp( dev, ifa->ifa_name ) == 0 ) )
+                    printf("%s %s\n", ifa->ifa_name, addressBuffer);
+            }
+            else if (ifa->ifa_addr->sa_family==AF_INET6 && show_ipv6 )
+            {
+                /**
+                 * IPv6 address, and we're showing them.
+                 */
+                tmpAddrPtr=&((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr;
+                char addressBuffer[INET6_ADDRSTRLEN];
+                inet_ntop(AF_INET6, tmpAddrPtr, addressBuffer, INET6_ADDRSTRLEN);
+                if ( ( dev == NULL ) ||
+                     ( strcmp( dev, ifa->ifa_name ) == 0 ) )
+                    printf("%s %s\n", ifa->ifa_name, addressBuffer);
+            }
+        }
+    }
+
+    if (ifAddrStruct!=NULL)
+        freeifaddrs(ifAddrStruct);
+
+    return 0;
+}