Syntax/Rules (Can I do this?)

yongho · #1 (**permalink**) 06-22-2005

I have a small piece of code that I need to iterate 24 times (for each hour of a day).... here's what it looks like now...

Code:

while read hour file; do
       
    if [ $hour -eq 00 ]; then
        count=`awk -F, 'BEGIN { count=0 } ............. { count++ } END { print count }' $file`
        hourly01=`expr $hourly1 + $trade_count`
    elif [ $hour -eq 01 ]; then
        count=`awk -F, 'BEGIN { count=0 } ............. { count++ } END { print count }' $file`
        hourly02=`expr $hourly2 + $trade_count`
    ..................
    fi

done < ls.txt

As you can see it's simple, and iterates over and over, but unneccessarily (24 times)... Could I replace all the numbers with one variable... like such..

don't take my code letter for letter, just take the idea and tell me if it can be done..

Code:

for (x=00; x<=23; x++) {
    if [ $hour -eq $x ]; then
        count=`awk -F, 'BEGIN { count=0 } ............. { count++ } END { print count }' $file`
        hourly$x=`expr ${hourly}$x + $trade_count`
    fi
}

Thats' the idea.. I know that I didn't use a unix for-loop, but I just started learning unix and I didn't check what the for looks like in unix yet).. But can I write the middle section (every occurence of $x) the way that I wrote it here?

jim mcnamara · #2 (**permalink**) 06-22-2005

awk supports arrays.

The

Code:

'{ count=0 } ............. { count++ } END { print count }'

part could write to an array element instead of "print count". Instead of going crazy over this, consider a good book like the O'Reilly book 'sed & awk' If you're in Manhattan, Barnes and Noble has it.

Short answer: in awk you can do what you asked. All in one piece of awk code.

yongho · #3 (**permalink**) 06-23-2005

I'm now considering doing it in the way you suggested, but I have another question about your suggested method.

My problem: Originally I ran something like ls -al | grep Jun 22 | cut -c49-100 >> myLs.txt to give me just the time and filename of all files for June 22nd in a text file.

With that text file I began awking.

You're suggesting that instead of using while read hour file that I begin the awk right away, to avoid repeating all that code that I did.

Since the text file with the LS holds the filenames of CSV files, I need to be able to, at some point, awk those files to perform some count calculations. I don't think I could use a nested awk.. awk within an awk to open those files found in the first awk. (or could I?).

I'll pick up the book over the weekend, thanks.

jim mcnamara · #4 (**permalink**) 06-23-2005

awk supports the system() function just like in C and php.

You can create a dynamic string, then pass it to system to create output.

It's not that awk is better than script or vice-versa - it's just bad to keep using several different tools and bouncing back and forth among them. IMO.

thepicoman · #5 (**permalink**) 06-26-2005

you typen in sudo a the biginng of the program coman to override the scynan cheak.

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