03-10-2005
Quote:
Originally Posted by eff_cee
Hi,
I've a question on awk. In English I want to:
(a) open a file, (b) search through the file for records where length of field15 > 20 characters and (c) print out some fields in the record.
I've written the following and it works OK. The trouble is this will ALWAYS write out the column headings irrespective of whether any records match the > 20 characters rule. Thus an output file will always be created. I only want to output anything IF the search criteria is satisfied.
I've tried moving the BEGIN part to after the search predicate (ie the length$15 > 20), but awk doesn't seem to like it. From reading the documentation the BEGIN command is invoked before any file is opened for searching. Does this mean that the BEGIN must be at the start of the statement ? I could nest the code inside another if (awk?) statement, but there must be a cleverer way? Any ideas ?
awk -F, 'BEGIN {print '\""${ROWDELIM}\n\""' \
'\""${HEAD1}\n\""' \
'\""${ROWDELIM}\n\""' \
'\""${HEAD2}\""'} \
length($15) > 20 \
{print $1","$3","$15, ++n \
} END {print "RECORD COUNT IS: " n}' $INPUTFILE > $TEXTFILE
Thanks
BEGIN statement is used to initialize that text formatting operation. In your case, operation like field15 > 20 has to be done in the operational area.
what is there in ${ROWDELIM}, ... ${HEAD2} variable. You have to include with awk -v <variable>=value
plz. give your sample three line input and expected output so that it will be more easy to accomplish your requirement.
hth.
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IGAWK(1) Utility Commands IGAWK(1)
NAME
igawk - gawk with include files
SYNOPSIS
igawk [ all gawk options ] -f program-file [ -- ] file ...
igawk [ all gawk options ] [ -- ] program-text file ...
DESCRIPTION
Igawk is a simple shell script that adds the ability to have ``include files'' to gawk(1).
AWK programs for igawk are the same as for gawk, except that, in addition, you may have lines like
@include getopt.awk
in your program to include the file getopt.awk from either the current directory or one of the other directories in the search path.
OPTIONS
See gawk(1) for a full description of the AWK language and the options that gawk supports.
EXAMPLES
cat << EOF > test.awk
@include getopt.awk
BEGIN {
while (getopt(ARGC, ARGV, "am:q") != -1)
...
}
EOF
igawk -f test.awk
SEE ALSO
gawk(1)
Effective AWK Programming, Edition 1.0, published by the Free Software Foundation, 1995.
AUTHOR
Arnold Robbins (arnold@skeeve.com).
Free Software Foundation Nov 3 1999 IGAWK(1)