how to join ifconfig output to a line per interface

Question

how do i convert the following output with sed? from:

lo0: flags=2001000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4,VIRTUAL> mtu 8232 index 1
    inet 127.0.0.1 netmask ff000000
igb0: flags=9040843<UP,BROADCAST,RUNNING,MULTICAST,DEPRECATED,IPv4,NOFAILOVER> mtu 1500 index 2
    inet 10.1.1.1 netmask ffffff00 broadcast 10.1.1.255
    groupname mnic_data

to:

lo0: flags=2001000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4,VIRTUAL> mtu 8232 index 1 inet 127.0.0.1 netmask ff000000
igb0: flags=9040843<UP,BROADCAST,RUNNING,MULTICAST,DEPRECATED,IPv4,NOFAILOVER> mtu 1500 index 2 inet 10.1.1.1 netmask ffffff00 broadcast 10.1.1.255 groupname mnic_data

I have tried

sed -n '/^[a-z]/{x;1!s/\n/ /g;1!p;};H'

but no luck! appreciate your help in advance

Answer 1

ifconfig |
awk '
    FNR>1 && /^[^[:space:]]/ {print ""}
    {printf "%s", $0}
    END {print ""}
'

Answer 2

You can try this:

$ sed -e :a -e '$!N;s/\n / /;ta' -e 'P;D' inputfile
lo0: flags=2001000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4,VIRTUAL> mtu 8232 index 1    inet 127.0.0.1 netmask ff000000
igb0: flags=9040843<UP,BROADCAST,RUNNING,MULTICAST,DEPRECATED,IPv4,NOFAILOVER> mtu 1500 index 2    inet 10.1.1.1 netmask ffffff00 broadcast 10.1.1.255    groupname mnic_data

EDIT: To get rid of the extra spaces in the output above, you can use:

$ sed -e :a -e '$!N;s/\n\s\+/ /;ta' -e 'P;D' inputfile
lo0: flags=2001000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4,VIRTUAL> mtu 8232 index 1 inet 127.0.0.1 netmask ff000000
igb0: flags=9040843<UP,BROADCAST,RUNNING,MULTICAST,DEPRECATED,IPv4,NOFAILOVER> mtu 1500 index 2 inet 10.1.1.1 netmask ffffff00 broadcast 10.1.1.255 groupname mnic_data

Answer 3

does this help (awk)?

awk '/:/&&f{print ""}{printf "%s", $0;f=1}'

test

kent$  echo "lo0: flags=2001000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4,VIRTUAL> mtu 8232 index 1
    inet 127.0.0.1 netmask ff000000
igb0: flags=9040843<UP,BROADCAST,RUNNING,MULTICAST,DEPRECATED,IPv4,NOFAILOVER> mtu 1500 index 2
    inet 10.1.1.1 netmask ffffff00 broadcast 10.1.1.255
    groupname mnic_data"|awk '/:/&&f{print ""}{printf "%s", $0;f=1}'
lo0: flags=2001000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4,VIRTUAL> mtu 8232 index 1    inet 127.0.0.1 netmask ff000000
igb0: flags=9040843<UP,BROADCAST,RUNNING,MULTICAST,DEPRECATED,IPv4,NOFAILOVER> mtu 1500 index 2    inet 10.1.1.1 netmask ffffff00 broadcast 10.1.1.255    groupname mnic_data