GREP or AWK assistance

[rkasowan]

Hello world-

I think I need to learn AWK. I am trying to pull simple info from a command to be stored as a variable.

I need to get the /dev/disk? and mount point for a particular drive.

I'm using:

diskutil info /Volumes/'Macintosh HD' | grep 'Part Of Whole" | cut -c30-34

and

diskutil info /Volumes/'Macintosh HD' | grep 'Mount Point" | cut -c30-44

But I'm running into big problems for obvious reasons. The volume information changes, the device number may be higher than 9 or the data is just unusually long. Its not a clean method.

How do I get the information I need form the standard output without using GREP and CUT? There has to be a better way, I just can't find it.

Any help would be greatly appreciated.

Thanks in advance!

- robbie -

[burschik]

It might be a good idea to include information about the output you get and what exactly you need to extract. Not everyone uses a Mac, you know.

[rkasowan]

Sorry for the confusion. I'm a rookie and live in a Mac world.

Its more a general question. I have no idea how to use AWK or other advanced tools. I'm trying but is not going so well. I could get similar information from hdiutil or other commands - diskutil is just this example.

I'm trying to find out how to best get the info I need.

The output I get is:

administrator:~ administrator$ diskutil info /Volumes/Untitled 
   Device Identifier:        disk2s2
   Device Node:              /dev/disk2s2
   Part Of Whole:            disk2
   Device / Media Name:      Untitled

   Volume Name:              Untitled
   Mount Point:              /Volumes/Untitled
   File System:              Journaled HFS+
                             Journal size 16384 KB at offset 0x189c000
   Owners:                   Disabled

   Partition Type:           Apple_HFS
   Bootable:                 Is bootable
   Media Type:               Generic
   Protocol:                 FireWire
   SMART Status:             Not Supported
   Volume UUID:              36AFDD45-AB5B-392D-BC32-0D3080618B28

   Total Size:               148.7 Gi (159697911808 B) (311909984 512-byte blocks)
   Free Space:               148.7 Gi (159666061312 B) (311847776 512-byte blocks)

   Read Only:                No
   Ejectable:                Yes
   Whole:                    No
   Internal:                 No

I would like to know how to get just the "disk2" from "Part Of Whole:".

I can grep and cut - but if I'm dealing with drive #10 then I'm in trouble because my grep and cut would leave me with disk1 because I have to cut the line without the spaces.

I use:

administrator:~ administrator$ diskutil info /Volumes/Untitled | grep 'Part Of Whole:' | cut -c30-34
disk2

So I get what I want but only if I know exactly how many characters it is.

I'm not sure what I need to do. Thats why I'm throwing it out to the people that know way more than I do.


As always if anyone can enlighten me I would appreciate it. Thanks in advance!

- robbie -

[secondmouse]

try

diskutil info /Volumes/Untitled | awk 'BEGIN{FS="[: ]+"}/Part Of Whole/{print $5}'

If you really want to make cut to work, try

diskutil info /Volumes/Untitled | grep "Part Of Whole" | cut -d ':' -f 2 | tr -d ' '

I prefer the awk approach because it requires only on command after the first pipe.

[burschik]

In a Linux programming forum, you should not expect anyone to be acquainted with a Mac-specific program like "diskutil". You could also use sed:

diskutil info /Volumes/Untitled | sed -n 's/[\t ]*Part Of Whole:[\t ]*\([[:alnum:]]\+\)/\1/p'