Problems with reg.-expressions in a awk-search-pattern

Shell Programming and Scripting
1

Hi,

i have some problems with regular expressions in a awk search pattern.

what i want to do:
i want to calculate the mean-value in the time from 00:00 to 06:00

how my data looks like:

....
04/01/13-01:40  670992  54802   80711   116460  156177  
04/01/13-01:50  703725  60150   85498   118844  154391  
04/01/13-02:00  639716  54841   79710   112262  153321
.....

what i tried so far:
i use the timestamp 04/01/13-hh:mm to filter my calculation.
the calc of the mean over the whole day works fine with

awk \04/01/13\ '{a+=$2} END{print a/NF}' file.txt

but when i try to extend the pattern like ..

awk \04/01/13-0[0-5]\ '{a+=$2} END{print a/NF}' file.txt

awk will crash.
can someone give me a hint please.

Thanks in advance!
IMPe

2

What do you mean 'awk will crash'?

I'm amazed these worked either way honestly -- you can't have code outside the quote like that...

awk '/04\/01\/13-0[0-5]/ { a+=$2 ; b++ } END { print a/b }' file.txt
1 Like
3

You have to escape the forward slash:

awk '/04\/01\/13-0[0-5]/{a+=$2;n=NF}END{print a/n}' file.txt
1 Like
4

Thanks a lot to both of you, corona688 and yoda.
Now it works fine, but when i try to change my time in the searchpattern, i.e. from 06-11
[ to take the data in between 06:00 - 12:00 ] i struggle again!
Can you please give me one more helping hand?

Thanks
IMPe

---------- Post updated at 01:41 AM ---------- Previous update was at 12:03 AM ----------

i think i found a way.
putting a seperate beginning and a end of the reg-expression ...

awk '/04\/01\/13-00/,/04\/01\/13-05:50/  {a+=$2;n=NF}END{print a/n}' file.txt

.... it seems to work fine.