Shell Programming and Scripting

Hi i have following file

uuid ( RO) : 62701790-60da-dd9a-669d-a563aac1c435
host-uuid ( RO): 5f3f668d-a7c7-4e5f-a4a6-6e90fafb50ed
sr-uuid ( RO): 62103d07-e0aa-acf3-2d9f-414ad3377bd0
device-config (MRO): location: /dev/xapi/block
currently-attached ( RO): true


uuid ( RO) : 99158eac-8cce-39bd-4893-8576e7f18234
host-uuid ( RO): 5f3f668d-a7c7-4e5f-a4a6-6e90fafb50ed
sr-uuid ( RO): 3a1ff5ac-ed95-1deb-da89-ebc3459d0ae8
device-config (MRO): port: 3260; SCSIid: 149455400000000000000000001000000710300000d000000; target: 10.0.71.71; targetIQN: iqn.2001-04.com.example:storage.disk2.sys1.xyz
currently-attached ( RO): true


uuid ( RO) : 4a65094e-8e85-46e6-2c68-0987fe14decd
host-uuid ( RO): 5f3f668d-a7c7-4e5f-a4a6-6e90fafb50ed
sr-uuid ( RO): 655ad503-1a5f-1221-9181-9a5fb37cb672
device-config (MRO): location: /dev/xapi/cd
currently-attached ( RO): true


uuid ( RO) : a871cc47-185a-7886-5e7f-e2e6c0fb18e0
host-uuid ( RO): 5f3f668d-a7c7-4e5f-a4a6-6e90fafb50ed
sr-uuid ( RO): db6cece4-4847-ae2f-2b0b-f3901697e2b3
device-config (MRO): device: /dev/sdd
currently-attached ( RO): true


uuid ( RO) : 26c74e8b-d931-70a5-11b7-2f36262d116a
host-uuid ( RO): 5f3f668d-a7c7-4e5f-a4a6-6e90fafb50ed
sr-uuid ( RO): 762f3b74-aab9-8f7f-887d-15c1886314e0
device-config (MRO): device: /dev/sdc
currently-attached ( RO): true


so the file is still big now my question is i want to extract the UUID of (RO) of the any device if i pass as argument like "/dev/sdc" then it should pass me that particular uuid (RO) as "26c74e8b-d931-70a5-11b7-2f36262d116a" so can anybody tells wht exact command ? i trdied with awk and grep still not able to reach the final.

Thanks

Many ways to do this... But it is a bit tricky.

Code:

find_uuid() {
  dev=$1
  awk '/^uuid/ { uuid=$3 } /^device-config/ && $NF == '$dev' { print uuid }' uuid-file
}

You'll need to change the filename (uuid-file) to the one you want (or empty for stdin). Then just do "find_uuid /dev/sdc" from the shell.

The trick is in realizing that awk is a series of pattern-script pairs, not just one. The first one is used to remember the most-recently seen uuid. The second prints it out when the device name matches.

Really not following here can i know what does mean of $3 here? can you give another trick if u know?
Thanks

$3 should be the uuid, but maybe it should be $NF (the last field in the line). Try that instead.

i want now include in script rather just want to try from Command line like this

cat dev.txt | awk '/^uuid/ { uuid=$3 } /^device-config/ && $NF == '/dev/sdc' { print uuid }'

But nothing it displaying

Code:

awk '/^uuid/ { uuid=$3 } /^device-config/ && $NF == "/dev/sdc" { print uuid }' dev.txt

Another way is to set the field separator to ": "

Code:

awk -F": " '$1 ~ /^uuid/ { uuid=$2 };  $1 ~ /^device-config/ && $3 == "/dev/sdc" { print uuid }'  dev.txt