[SOLVED] awk help!!

ashok.g · 12-16-2009, 04:56 AM

Look at the following code:

Code:

date|awk '{print $4}'|awk -F ":" '{print $1}'>temp
a=`cat temp`

insted of moving some data into temp and then taking into a variable a,why can't we assign the value directly to variable,a like:

Code:

a=date|awk '{print $4}'|awk -F ":" '{print $1}'

druuna · 12-16-2009, 05:12 AM

Hi,

You can:

a="`date|awk '{print $4}'|awk -F ":" '{print $1}'`"
or
a=$(date|awk '{print $4}'|awk -F ":" '{print $1}')

Both methods execute the date | awk ..... part first and put the output in the variable.

Hope this helps.

ashok.g · 12-16-2009, 05:19 AM

Thanks for your reply.

Quote:

Originally Posted by druuna

a=$(date|awk '{print $4}'|awk -F ":" '{print $1}')"

I think you wrongly typed " there.

druuna · 12-16-2009, 05:21 AM

Yep I did, I'll correct the typo in my original reply.

ghostdog74 · 12-16-2009, 06:10 AM

no need to use awk 2 times!!

Code:

date|awk '{split($4,f,":");print f[1]}'

or

Code:

date|awk -F"[: ]" '{print $4}'

ashok.g · 12-16-2009, 06:23 AM

Quote:

Originally Posted by ghostdog74

Code:

date|awk -F"[: ]" '{print $4}'

Can you explain me the above command?

pixellany · 12-16-2009, 07:52 AM

Quote:

Originally Posted by ashok.g

Can you explain me the above command?

The output of "date" is piped into awk.

Based on the defined field separator, the 4th field is printed.

Which part do you not understand? HINT: You can use regexes when defining field separators.

ashok.g · 12-17-2009, 12:25 AM

Quote:

Originally Posted by pixellany

Which part do you not understand?

What matches that field separator you used?I know that "[ ]" is used to match the character containing in that but you used ": " there. Actually the output of date doesn't contain any substring matching with ": ". Did you catch my point?

catkin · 12-17-2009, 12:36 AM

Quote:

Originally Posted by ashok.g

What matches that field separator you used?I know that "[ ]" is used to match the character containing in that but you used ": " there. Actually the output of date doesn't contain any substring matching with ": ". Did you catch my point?

[ ] is used to list a range of characters so, in this case, input lines will be split into words separated by ":" or " ".

ashok.g · 12-17-2009, 12:43 AM

Thank you...