AWK print unexpected newline or end of string inside shell

Question

I have a shell script which is trying to trim a file from end of the line but I always get some error.

Shell Script:

AWK_EXPRESSION='{if(length>'"$RANGE1"'){ print substr('"$0 "',0, length-'"$RANGE2"'}) } else { print '"$0 "'} }'

for report in ${ACTUAL_TARGET_FOLDER}/* ; do
  awk $AWK_EXPRESSION $report > $target_file
done

If I trigger the AWK command, I get unexpected newline or end of string near print.

What am I missing?

Is $0 supposed to be replaced by the shell or is the intention to pass it to awk as $0? — Joni, Jul 25 '20 at 20:24
Related: [I'm trying to put a command in a variable, but the complex cases always fail!](http://mywiki.wooledge.org/BashFAQ/050) — John1024, Jul 25 '20 at 21:06
Are you aware this overwrites the target file for every report? — glenn jackman, Jul 25 '20 at 22:57
Please read https://mywiki.wooledge.org/Quotes as you have several quoting bugs. — Ed Morton, Jul 25 '20 at 23:15

score 2 · Answer 1 · answered Jul 25 '20 at 21:24

Why are you trying to store the awk body in a shell variable? Just use awk and the -v option to pass a shell value into an awk variable:

awk -v range1="$RANGE1" -v range2="$RANGE2" '{
    if (length > range1) {
        print substr($0,0, length-range2)
    } else { 
        print 
    }
}' "$ACTUAL_TARGET_FOLDER"/* > "$target_file"

Add a few newlines to help readability.

Get out of the habit of using ALLCAPS variable names, leave those as reserved by the shell. One day you'll write PATH=something and then wonder why your script is broken.

Unquoted variables are subject to word splitting and glob expansion. Use double quotes for all your variables unless you know what specific side-effect you want to use.

thanks @glenn used what Joni have suggested and your insight also helped... Thanks! — Rasmi, Jul 25 '20 at 22:12

Joni · Accepted Answer · 2020-07-25T23:16:57.040

1

I would recommend writing the AWK program using AWK variables instead of interpolating variables into it from the shell. You can pass variable into awk on the command line using the -v command line option.

Also, awk permits using white space to make the program readable, just like other programming languages. Like this:

AWK_EXPRESSION='{
  if (length > RANGE1) {
    print substr($0, 1, length-RANGE2)
  } else {
    print
  }
}'

for report in "${ACTUAL_TARGET_FOLDER}"/* ; do
  awk -v RANGE1="$RANGE1" -v RANGE2="$RANGE2" "$AWK_EXPRESSION" "$report" > "$target_file"
done

edited Jul 25 '20 at 23:16

answered Jul 25 '20 at 21:26

Joni

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Thanks @joni this helped and worked for me... was breaking my head whole day today on this. – Rasmi Jul 25 '20 at 22:11

AWK print unexpected newline or end of string inside shell

2 Answers2