Parse multiple awk variables in a "for" loop bash

Question

I am trying to parse multiple awk variables into a for loop. I have a document that consists of multiple fields separated by a comma. Each field is capture by awk and I want to use these variables to create multiple instances of text in an additional file. I have used "while" to capture the variables, but this only runs once.

awk -F ',' '{print $1,$2,$3}' extensions.txt | while read var1 var2 var3; do
            echo " <item context=\"active\" type=\"\" fav=\"false\" mod=\"true\" index=\"0\">
            <number>$var3</number>
            <number_type>sip</number_type>
            <first_name>$var1</first_name>
            <last_name>$var2</last_name>
            <organization>Stackoverflow</organization>
            </item>" > test.txt
done
exit

Output for test.txt is:

        <item context=\"active\" type=\"\" fav=\"false\" mod=\"true\" index=\"0\">
        <number>123456789</number>
        <number_type>sip</number_type>
        <first_name>Jon</first_name>
        <last_name>Doe</last_name>
        <organization>Stackoverflow</organization>
        </item>

If I use a for loop, it won't retain the 3 variables seperately, but rather take the combined output and place it into a single variable.

The trailing exit is pretty pointless; the shell will exit anyway if you delete the line and it is the last (non-blank, non-comment) line in the script. — Jonathan Leffler
– Jonathan Leffler, Commented Jun 28, 2016 at 6:37
Note that each iteration of the loop clobbers the file test.txt. Either place the output redirection after, but on the same line as, the done, or use append mode >>. — Jonathan Leffler
– Jonathan Leffler, Commented Jun 28, 2016 at 6:38
You should really show a few (say 3) lines of input, plus the desired output, plus the actual output. — Jonathan Leffler
– Jonathan Leffler, Commented Jun 28, 2016 at 6:39
Hard to format the comment, but multiple line echo with embedded quotes is much cleaner written with a heredoc. egcat << EOF\n <item context="active...\nEOF — William Pursell
– William Pursell, Commented Jun 28, 2016 at 9:22

sat · Accepted Answer · 2016-06-28 07:59:39Z

4

You don't need to use awk. You can do it with bash itself by using IFS (Internal Field Separator).

Use this:

while IFS="," read v1 v2 v3 _
do
    echo "<item context=\"active\" type=\"\" fav=\"false\" mod=\"true\" index=\"0\">
    <number>$v1</number>
    <number_type>sip</number_type>
    <first_name>$v2</first_name>
    <last_name>$v3</last_name>
    <organization>Stackoverflow</organization>
    </item>";
done < extensions.txt > output.txt

edited Jun 28, 2016 at 7:59

answered Jun 28, 2016 at 6:35

sat

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2 Comments

Metalhhead22 Over a year ago

I just tested it and it does work indeed. Thanks man appreciate it!!! :)

Andreas Louv Over a year ago

You might want to add a dummy variable at the end to catch any potential four words lines: read -r v1 v2 v3 _ <<< "a,b,c,d,e,f" Will assign a, b and c to v1, v2 and v3, while d,e,f will be assigned to _.

John3136 · Accepted Answer · 2016-06-28 09:09:55Z

3

You could let Awk do all the work. Awk does process line by line, so put the awk in a file and use awk -f your_program.awk.

Something like this should work:

{
    print "<item content=\"active\" type=\"\" fav=\"false\" mod=\"true\" index=\"0\">"
    print "<number>"$1"</number>"
    print "<number_type>sip</number_type>"
    print "<first_name>"$2"</first_name>"
    print "<last_name>"$3"</last_name>"
    print "<organization>Stackoverflow</organization>"
    print "</item>"
}

edited Jun 28, 2016 at 9:09

answered Jun 28, 2016 at 6:37

John3136

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