{"id":666,"date":"2012-11-26T10:05:44","date_gmt":"2012-11-26T10:05:44","guid":{"rendered":"http:\/\/www.plugged.in\/?p=666"},"modified":"2019-04-17T19:59:18","modified_gmt":"2019-04-17T16:59:18","slug":"getting-network-information-in-bash-scripts","status":"publish","type":"post","link":"https:\/\/www.veriteknik.net.tr\/en\/getting-network-information-in-bash-scripts\/","title":{"rendered":"Getting Network Information in Bash Scripts"},"content":{"rendered":"

Sometimes when writing your bash scripts, you may need some information about the network, such as the IP addresses, both IPv4 and IPv6, broadcast addresses, netmasks and such. There are two very basic ways of getting the necessary information in Linux systems, you should either choose the ip addr show<\/strong> method, and parse what’s coming out of it, or parse the output of ifconfig<\/strong>. Let’s deal with them both.<\/p>\n

The “ip addr show” method<\/strong><\/p>\n

We will parse this output:<\/p>\n

eaydin@eaydin:~$ ip addr show\n1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN \n\u00a0\u00a0\u00a0 link\/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00\n\u00a0\u00a0\u00a0 inet 127.0.0.1\/8 scope host lo\n\u00a0\u00a0\u00a0 inet6 ::1\/128 scope host \n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 valid_lft forever preferred_lft forever\n2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000\n\u00a0\u00a0\u00a0 link\/ether 00:22:15:f6:55:e6 brd ff:ff:ff:ff:ff:ff\n\u00a0\u00a0\u00a0 inet 192.168.16.30\/24 brd 192.168.16.255 scope global eth0\n\u00a0\u00a0\u00a0 inet6 fe80::222:15ff:fef6:55e6\/64 scope link \n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 valid_lft forever preferred_lft forever<\/pre>\n
IP ADDRESS :<\/p>\n
ip addr show |grep -w inet |grep -v 127.0.0.1|awk '{ print $2}'| cut -d \"\/\" -f 1<\/pre>\n
Output : 192.168.16.30<\/pre>\n
PREFIX (Netmask in CIDR Notation) :<\/p>\n
ip addr show |grep -w inet |grep -v 127.0.0.1|awk '{ print $2}'| cut -d \"\/\" -f 2<\/pre>\n
Output : 24<\/pre>\n
Broadcast IP :<\/p>\n
ip addr show |grep -w inet |grep -v 127.0.0.1|awk '{ print $4}'<\/pre>\n
Output : 192.168.16.255<\/pre>\n
Device name :<\/p>\n
ip addr show | awk 'FNR==7 {print $2}' | tr -d :<\/pre>\n
Output : eth0<\/pre>\n
IPv6 ADDRESS :<\/p>\n
ip addr show |grep -w inet6 |grep -v ::1|awk '{ print $2}'| cut -d \"\/\" -f 1<\/pre>\n
Output : fe80::222:15ff:fef6:55e6<\/pre>\n
IPv6 PREFIX (Netmask in CIDR Notation) :<\/p>\n
ip addr show |grep -w inet6 |grep -v ::1|awk 'FNR==1 { print $2}'| cut -d \"\/\" -f 2<\/pre>\n
Output : 64<\/pre>\n
Ethernet Card MAC Address :<\/p>\n
ip addr show | grep -w ether | awk '{ print $2 }'<\/pre>\n
Output : 00:22:15:f6:55:e6<\/pre>\n
The “ifconfig” method<\/strong><\/p>\n
This time we’ll parse this output:<\/p>\n
eaydin@eaydin:~$ ifconfig\neth0      Link encap:Ethernet  HWaddr 00:22:15:f6:55:e6  \n          inet addr:192.168.16.30  Bcast:192.168.16.255  Mask:255.255.255.0\n          inet6 addr: fe80::222:15ff:fef6:55e6\/64 Scope:Link\n          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1\n          RX packets:626934 errors:0 dropped:0 overruns:0 frame:0\n          TX packets:363506 errors:0 dropped:0 overruns:0 carrier:2\n          collisions:0 txqueuelen:1000 \n          RX bytes:284072710 (284.0 MB)  TX bytes:56413838 (56.4 MB)\n          Interrupt:45 \n\nlo        Link encap:Local Loopback  \n          inet addr:127.0.0.1  Mask:255.0.0.0\n          inet6 addr: ::1\/128 Scope:Host\n          UP LOOPBACK RUNNING  MTU:16436  Metric:1\n          RX packets:43339 errors:0 dropped:0 overruns:0 frame:0\n          TX packets:43339 errors:0 dropped:0 overruns:0 carrier:0\n          collisions:0 txqueuelen:0 \n          RX bytes:4834972 (4.8 MB)  TX bytes:4834972 (4.8 MB)<\/pre>\n
IP ADDRESS :<\/p>\n
ifconfig | grep -w inet |grep -v 127.0.0.1| awk '{print $2}' | cut -d \":\" -f 2<\/pre>\n
Output : 192.168.16.30<\/pre>\n
Broadcast IP :<\/p>\n
ifconfig | grep -w inet |grep -v 127.0.0.1| awk '{print $6}' | cut -d \":\" -f 2\n\nOutput : 192.168.16.255<\/pre>\n
Netmask :<\/p>\n
ifconfig | grep -w inet |grep -v 127.0.0.1| awk '{print $4}' | cut -d \":\" -f 2<\/pre>\n
Output : 255.255.255.0<\/pre>\n
Device name :<\/p>\n
ifconfig | awk 'FNR==1 { print $1 }' | tr --d :<\/pre>\n
Output : eth0<\/pre>\n
IPv6 ADDRESS :<\/p>\n
ifconfig | grep -w inet6 | grep -v ::1| awk '{ print $2 }'\n\nOutput : fe80::222:15ff:fef6:55e6<\/pre>\n
IPv6 PREFIX (Netmask in CIDR Notation) :<\/p>\n
ifconfig | grep -w inet6 | awk 'FNR == 2 { print $4 }'<\/pre>\n
Output : 64<\/pre>\n
Ethernet Card MAC Address :<\/p>\n
ifconfig | grep -w ether | awk '{ print $2 }'<\/pre>\n
Output : 00:22:15:f6:55:e6<\/pre>\n","protected":false},"excerpt":{"rendered":"
Sometimes when writing your bash scripts, you may need some information about the network, such as the IP addresses, both IPv4 and IPv6, broadcast addresses, netmasks and such. There are two very basic ways of getting the necessary information in Linux systems, you should either choose the ip addr show method, and parse what’s coming […]<\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_uag_custom_page_level_css":"","footnotes":""},"categories":[370,386],"tags":[544],"yst_prominent_words":[1046,1038,1048,1041,1043,1040,1035,1045,1037,1034,839,1039,1031,1036,1033,1044,1042,1032,1030,1047],"class_list":["post-666","post","type-post","status-publish","format-standard","hentry","category-linux","category-network","tag-linux-bash-network-ifconfig-ip"],"jetpack_featured_media_url":"","uagb_featured_image_src":{"full":false,"thumbnail":false,"medium":false,"medium_large":false,"large":false,"1536x1536":false,"2048x2048":false},"uagb_author_info":{"display_name":"Mustafa Emre Ayd\u0131n","author_link":"https:\/\/www.veriteknik.net.tr\/en\/author\/eaydin\/"},"uagb_comment_info":0,"uagb_excerpt":"Sometimes when writing your bash scripts, you may need some information about the network, such as the IP addresses, both IPv4 and IPv6, broadcast addresses, netmasks and such. There are two very basic ways of getting the necessary information in Linux systems, you should either choose the ip addr show method, and parse what’s coming…","_links":{"self":[{"href":"https:\/\/www.veriteknik.net.tr\/en\/wp-json\/wp\/v2\/posts\/666","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.veriteknik.net.tr\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.veriteknik.net.tr\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.veriteknik.net.tr\/en\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.veriteknik.net.tr\/en\/wp-json\/wp\/v2\/comments?post=666"}],"version-history":[{"count":1,"href":"https:\/\/www.veriteknik.net.tr\/en\/wp-json\/wp\/v2\/posts\/666\/revisions"}],"predecessor-version":[{"id":6539,"href":"https:\/\/www.veriteknik.net.tr\/en\/wp-json\/wp\/v2\/posts\/666\/revisions\/6539"}],"wp:attachment":[{"href":"https:\/\/www.veriteknik.net.tr\/en\/wp-json\/wp\/v2\/media?parent=666"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.veriteknik.net.tr\/en\/wp-json\/wp\/v2\/categories?post=666"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.veriteknik.net.tr\/en\/wp-json\/wp\/v2\/tags?post=666"},{"taxonomy":"yst_prominent_words","embeddable":true,"href":"https:\/\/www.veriteknik.net.tr\/en\/wp-json\/wp\/v2\/yst_prominent_words?post=666"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}