Limitations of awk? Good idea? Bad idea? Post: 74262

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Top Forums Shell Programming and Scripting Limitations of awk? Good idea? Bad idea? Post 74262 by yongho on Wednesday 8th of June 2005 04:41:42 PM

06-08-2005

Registered User

Limitations of awk? Good idea? Bad idea?

Keeping in mind that I'm relatively comfortable with programming in general but very new to unix and korn/bourne shell scripts..

I'm using awk on a CSV file, and then performing calculations and operations on specific fields within specific records. The CSV file I'm working with has about 600 records, with 30 fields.

Since I want to be able to cross-reference one record against all other records multiple times for different/specific records that need to be checked (for example if a record orders an amendment to a previous record, I'd like to check to see if the previous record still exists), and since, I think, awk only runs through each record once, I wanted to know if it's possible, and if so, if it's even a good idea to store all the fields from each record that I need (I don't need all of them, just maybe a third of the information) into an array in awk, and then return the array itself, outside of awk.

Possible? Good idea, bad idea? I'm open to all suggestions and advice.
Note: I don't know if it's possible to run the loop for each record again once you're in the awk program, for example: a nested awk where in the middle of the loop for the host awk, you can start a second awk to check the current record in the original awk against all other records.

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LEARN ABOUT DEBIAN

dpkg-awk

DPKG-AWK(1)						      General Commands Manual						       DPKG-AWK(1)

NAME

       dpkg-awk - Utility to read a dpkg style db file

SYNOPSIS

       dpkg-awk [(-f|--file) filename] [(-d|--debug) ##] [(-s|--sort) list] [(-rs|--rec_sep) ??] '<fieldname>:<regex>' ... -- <out_fieldname> ..

DESCRIPTION

       dpkg-awk  Parses  a  dpkg status file (or other similarly formatted file) and outputs the resulting records.  It can use regex on the field
       values to limit the returned records, it can also be told which fields to output, and it can sort the matched fields.

OPTIONS

       -f filename
       --file filename
	      The file to parse.  The default is /var/lib/dpkg/status.

       -d [#]
       --debug [#]
	      Each time this is specified, it increased the debug level.

       -s field(s)
       --sort field(s)
	      A space or comma separated list of fields to sort on.

       -n field(s)
       --numeric field(s)
	      A space or comma separated list of fields that should be interpreted as numeric in value.

       -rs ??
       --rec_sep ??
	      Output this string at the end of each output paragraph.

       -h
       --help Display some help.

       fieldname
	      The fields from the file, that are matched with the regex given.	The fieldnames are case insensitive.

       out_fieldname
	      The fields from the file, that are output for each record.  If the first field listed begins with ^, then the list  of  fields  that
	      follows will NOT be output.

BUGS

       Be  warned  that  the author has only a shallow understanding of the dpkg packaging system, so there are probably tons of bugs in this pro-
       gram.

       This program comes with no warranties.  If running this program causes fire and brimstone to rain down upon the earth, you will be on  your
       own.

       This program accesses the dpkg database directly in places, querying for data that cannot be gotten via dpkg.

AUTHOR

       Adam Heath <doogie@debian.org>

DEBIAN
								 Debian Utilities						       DPKG-AWK(1)