bronto has asked for the wisdom of the Perl Monks concerning the following question:

Fellow monks

I am building an application that should read and collect data from many NetApp filers and store them in a database for making periodical usage reports. To avoid bothering production filers during the early stage of development I created a file for each filer containing the output of the quota report command.

The output looks like:

K-Bytes Files Type ID Volume Tree Used Limit Used Limit Quo +ta Specifier ----- -------- -------- -------- -------- -------- ------- ------- --- +------------ tree 7 data pre_appltop 3449512 4194304 30723 +- /vol/data/pre_appltop tree 6 data pre_appsdata 23327540 31457280 142938 + - /vol/data/pre_appsdata

To simulate the command output, I'd need to read the file line by line, print if it doesn't begin with tree, otherwise substitute the fifth field (say: $field[4] with int rand $field[4]). Since the dashed line on top of the report gave me an hint for creating a sprintf format, I found that this one-liner just does the job I need:

perl -pe 'next unless /^tree/ ; @f=split ; $f[4] = int rand $f[4] ; $_ = sprintf "%-5s %8d %-8s %-8s %8d %8d %7d %7d %-15s\n",@f'

But what if I hadn't any hint? How would you replace the fourth field leaving the line formatting in a sane state?

Thanks in advance for your suggestions


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