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Top Forums Shell Programming and Scripting Help a newbie please with awk if else statements Post 302244175 by otheus on Tuesday 7th of October 2008 11:12:07 AM
Old 10-07-2008
Looking at this again, I think you're confused about how awk works. Each line is compared to each pattern, in turn, and if there is a match, the "program" part (for each pattern that matches) is then run, in turn. After all input is consumed, THEN the "END" block is executed. To have one of these programs "skip" to the next line, use "next;". Further points:

1. I'm not sure what you are trying to do with the NR==1 line (you never write to new_fname). You can output to a file with "printf expr list >filename".

2. You're not using sprintf() in a meaningful way, except to avoid printing out a newline. You can just do "print $1, $38, $50", except that a newline will be appended. But I don't see why you're using it this way.

3. Instead of "END", you can have a "default" program at the end. Sometimes you have to give it an expression of "1". This way you can prepare your output and then have:

Code:
/pattern/ { program1 }
/pattern2/ { program 2 }
...
1 { print output >newfilename }

You can also put this at the beginning of the list of pattern-programs, and that way it will execute every time, regardless if a program uses "next". Here, however, you have to be sure that (1) you don't print out when there is nothing to print out, and (2) if you don't want to print out something, you empty the field.
Code:
length(output) { print output > newfilename } 

/badfield/ {  output=""; next; }
/goodfield/ { output=output "blah blah"; next; }
/other/ { output="fubar"; }
...

 

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GREP(1) 						      General Commands Manual							   GREP(1)

NAME
grep, g - search a file for a pattern SYNOPSIS
grep [ option ... ] pattern [ file ... ] g [ option ... ] pattern [ file ... ] DESCRIPTION
Grep searches the input files (standard input default) for lines that match the pattern, a regular expression as defined in regexp(7) with the addition of a newline character as an alternative (substitute for |) with lowest precedence. Normally, each line matching the pattern is `selected', and each selected line is copied to the standard output. The options are -c Print only a count of matching lines. -h Do not print file name tags (headers) with output lines. -e The following argument is taken as a pattern. This option makes it easy to specify patterns that might confuse argument parsing, such as -n. -i Ignore alphabetic case distinctions. The implementation folds into lower case all letters in the pattern and input before interpre- tation. Matched lines are printed in their original form. -l (ell) Print the names of files with selected lines; don't print the lines. -L Print the names of files with no selected lines; the converse of -l. -n Mark each printed line with its line number counted in its file. -s Produce no output, but return status. -v Reverse: print lines that do not match the pattern. -f The pattern argument is the name of a file containing regular expressions one per line. -b Don't buffer the output: write each output line as soon as it is discovered. Output lines are tagged by file name when there is more than one input file. (To force this tagging, include /dev/null as a file name argument.) Care should be taken when using the shell metacharacters $*[^|()= and newline in pattern; it is safest to enclose the entire expression in single quotes '...'. An expression starting with '*' will treat the rest of the expression as literal characters. G invokes grep with -n and forces tagging of output lines by file name. If no files are listed, it searches all files matching *.C *.b *.c *.h *.m *.cc *.java *.cgi *.pl *.py *.tex *.ms SOURCE
/src/cmd/grep /bin/g SEE ALSO
ed(1), awk(1), sed(1), sam(1), regexp(7) DIAGNOSTICS
Exit status is null if any lines are selected, or non-null when no lines are selected or an error occurs. GREP(1)
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