nixCraft

ricc · #1 (**permalink**) 08-09-2005, 05:08 PM

Hi all,
I want to write a script that will use the o/p from another utility and act upon a certain field from the third line onwards

Lets suppose, the who command o/p contained a few unwanted lines in the beginning. Like this

#who
this is the output of the who commnd
the users cuttently logged in are
root pts/0 Aug 9 14:55 (172.17.0.1)
root pts/1 Aug 9 15:58 (172.17.0.1)

Now suppose, I want to act upon the fist field, i.e. (usernames in this case)

If I write the script as

#for i in `who |cut -f1 -d" "`; do echo "these are the users logged on : $i ";done

This will also output --this and the

But I don't want "this and the". So what shall I do so that it escapes the 1st and 2nd lines and starts acting on the 1st field from the 3rd line onwards till the last one.

Can any one please tell me how to do this.

Thanks in advance for any help.

rc

rockdalinux · #2 (**permalink**) 08-09-2005, 05:18 PM

Hmm

Quite esay I guess

Code:

for i in $(who |cut -f1 -d" "|grep -vE "(this|the)" ); do echo "these are the users logged on : $i ";done

grep -v will inform not to display the word this or the

ricc · #3 (**permalink**) 08-10-2005, 01:09 PM

Thank you Rocky,

I knew you would certainly reply. Thank you for the solution. I also want to know what if the o/p of who is like this

Code:

  
# who
these are the users who are currently logged in
-------------------------------------------------------
ram      :0           Aug 10 11:27 (console)
ram     pts/0        Aug 10 11:57 (192.168.2.50)

Now, the 1st field after cutting contains

these
-------------------------------------------------------
ram
ram

Now tell me how do I isolate the
-------------------------------------------------------

I depend on you rocky. I believe you can help me.

Cheers

rc

rockdalinux · #4 (**permalink**) 08-10-2005, 04:50 PM

It is same as above, here is what you need to first one:

Code:

for i in $(who |cut -f1 -d" "|grep -vE "(^-|this|the)" ); do echo "these are the users logged on : $i ";done

ricc · #5 (**permalink**) 08-11-2005, 10:59 AM

Thank you Rocky. You are just great. I knew I can depend on you.

Long live Shell scripting and long live Rocky.

rc

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