Open-Vswitch creates virtual interfaces, they all have this pattern: s[digit]-eth[digit] For example: s1-eth1, s1-eth2, s12-eth3, s2-eth3 ...
I want to show information of -for example- all interfaces starting with s1 (in our example, it must give s1-eth1 and s1-eth2).
I tried this command, but it shows only the first line of information:
I am more interested about information like RX packets, TX packets, erros, HWaddr.. like this:
ifconfig's output has a blank line between each interface, making it perfectly suited for reading and processing in "paragraph mode" in a scripting language like awk or perl. A "paragraph" is any block of text separated from other blocks by one-or-more empty lines.
For example:
ifconfig | awk -v RS='' '/^s1-eth[12]:/ {print}'
The awk example above sets awk's record separator (RS) to the empty string, causing it to process paragraphs instead of individual lines. In this case, each paragraph is tested for a match against ^s1-eth[12]: and is printed if it matches.
Example output from my system:
$ ifconfig | awk -v RS='' '/^(ppp0|lo):/ {print}'
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
loop txqueuelen 1000 (Local Loopback)
RX packets 64237556 bytes 36962222928 (34.4 GiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 64237556 bytes 36962222928 (34.4 GiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
ppp0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST> mtu 1412
inet ip.ip.ip.ip netmask 255.255.255.255 destination ip.ip.ip.ip
ppp txqueuelen 3 (Point-to-Point Protocol)
RX packets 28220997 bytes 19305565357 (17.9 GiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 21719890 bytes 3009382446 (2.8 GiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
Note that this is no longer printed in paragraphs - there is no empty line between each interfaces "record". If you want paragraphs in your output, set the output record separator (ORS) to two newlines (\n\n). e.g.
ifconfig | awk -v RS='' -v ORS='\n\n' '/^(ppp0|lo):/ {print}'
To do something similar with ip's output rather than ifconfig's is slightly more complicated. ip doesn't produce neatly paragraph-separated output. It does, however, output each interface in a block with the interface's number followed by a colon and a space at the beginning of a line, with the rest of that interfaces details following.
To make use of this, set RS to the regular expression ((^|\n)[0-9]+:). That matches any digits followed by a colon and a space ([0-9]+:) that are either at the beginning of the file (^, to match the first record, which would otherwise be skipped) or immediately after a newline.
For example, on my system:
$ ip addr | awk -v RS='(^|\n)[0-9]+: ' '/^(lo|eth0):/ {print}'
lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master br0 state UP group default qlen 1000
link/ether 01:33:ed:b0:13:a9 brd ff:ff:ff:ff:ff:ff
(my eth0 doesn't have any IP addresses because I have it set up as a bridge for VMs and docker containers. The IP addresses are on the br0 interface instead)
You could use grep -An to print the matching line and the n following ones, but that is a bit untidy since the number of lines may vary.
Probably better to use awk. This would print all sections that start with enp1 or enp3. The first rule !/^ / {p=0} clears the variable p if the line does not start with a space, the second /^enp[13]/ {p=1} sets if it the line starts with the interface names we want, and then we print if p is set. The lines that start with spaces only match the last rule, so they're printed based on the previous value of p.
# /sbin/ifconfig -a |awk '!/^ / {p=0} /^enp[13]/ {p=1}; p'
enp1s0 Link encap:Ethernet HWaddr ...
inet addr:...
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:135284106 errors:0 dropped:0 overruns:0 frame:0
TX packets:144695 errors:0 dropped:0 overruns:0 carrier:2
collisions:0 txqueuelen:1000
RX bytes:8292624956 (8.2 GB) TX bytes:16595674 (16.5 MB)
enp3s0 Link encap:Ethernet HWaddr ...
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
In your case, you'd of course use a pattern like /^s1-eth/.
I want to show information of -for example- all interfaces starting with
s1
Using net-tools:
ifconfig | grep s1 -A9
Using iproute2:
ip -s link | grep s1 -A7
For your current ifconfig output:
ifconfig | grep -A7 --no-group-separator '^s1-eth'
For post-processing, with newer versions of iproute2 you may want to use the JSON output format that is meant for that:
ip -j -s link show |
jq -r '
.[]|
select(.ifname|test("^s\\d+-eth\\d+$"))|
[.ifname, .stats64.rx.bytes, .stats64.tx.bytes]|
@csv'
For instance to get a CSV output with interface name, RX and TX bytes.
ifconfig | awk '/^s[[:digit:]]+-eth[[:digit:]]+:/ {flag=1} /!^[[:digit:]]+-eth[[:digit:]]+:/ {flag=0}flag'
Using awk, pattern match to as outlined, setting a print flag to 1 if it exists and 0 if not. Print based on flag.
Previous answers suggested:
ifconfig: which is deprecated.
ip -s link: which doesn't display all the information that ifconfig displays (such as IP address).
I wanted to offer another command that worked for me. So if you're looking for IP address(es) of an interface, you might consider:
For the raw interface output:
ip a | grep s1 -A3
For IPv4 only:
ip -4 a | grep s1 -A1
ip a is an abbrevation for ip address. -A1 and -A3 paremeters determine the number of lines to display after the last occurrence of your text. If you modify the parameters in ip command, you can change the -A parameter's number to fit as well.
