How to print a column using awk command line and add header

Question

I have a problem and would appreciate any assistance. I have test1.txt file with the following columns:

column1|column2|column3|column4|column5|column6|column7|column8|

I then run the following to target specific columns.

cat test1.txt | awk -F "|" '{ print $2, $3, $4, $6, $7}' > teste.csv

The CSV file outputs the result in 1 line like so:

column2 column3 column4 column6 column7

but what i want is something like

header2|header3|header4|header6|header7
column2|column3|column4|column6|column7

Would you be able to help me fix the above and - also how can i then add headers after getting the correct result.

Thanks in advance

Please add your desired output (no description) for that sample input to your question (no comment). — Cyrus
– Cyrus, Commented Oct 26, 2020 at 12:10
@Maskiin Thank you. No problem. As you are new here, it's normal that you don't know all the "rules" of this site. — Bodo
– Bodo, Commented Oct 26, 2020 at 15:45

Bodo · Accepted Answer · 2020-10-26 13:05:37Z

5

If the problem is that the columns should be separated with | instead of space, you have to set the output field separator OFS to the same value as the input field separator FS.

awk -F "|" -v 'OFS=|' '{ print $2, $3, $4, $6, $7}' test1.txt > teste.csv

You can use the BEGIN condition to add commands for printing a header. In this case you also can put the assignement to OFS there.

awk -F "|" 'BEGIN { OFS=FS; print "header2|header3|header4|header6|header7" } { print $2, $3, $4, $6, $7}' test1.txt > teste.csv

With the input shown in the question this prints

header2|header3|header4|header6|header7
column2|column3|column4|column6|column7

edited Oct 26, 2020 at 13:05

answered Oct 26, 2020 at 12:21

Bodo

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4 Comments

Maskiin Over a year ago

Thanks.I have tried but still it shows like below ``` header2|header3|header4|header6|header7 column2FScolumn3FScolumn4FScolumn6FScolumn7 ```

Bodo Over a year ago

@Maskiin Please also edit your question as suggested in the comments below your question. This site is not only to answer the question for you personally, but also serves as a reference for others that may have a similar question. That's why your question should be clear and easy to understand. Currently the answers are partially based on guessing about your requirements.

Maskiin Over a year ago

happy to edit my question - it doesn't let me. I am new to the site apologies in advance for my ignorance

Bodo Over a year ago

@Maskiin Below your question there should be written in gray something like "share edit delete flag". Click on "edit" to edit your question.

Raman Sailopal · Accepted Answer · 2020-10-26 12:37:37Z

1

Given that you have referenced a csv (comma separated value output in your question), wit th sample data in the file columns, you can run:

awk -F\| 'BEGIN { OFS=",";print "COLUMN1"OFS"COLUMN2"OFS"COLUMN3"OFS"COLUMN4"OFS"COLUMN5"OFS"COLUMN6"OFS"COLUMN7"OFS"COLUMN8"OFS } { $1=$1 }1' columns

Set the output to , in the BEGIN section and print the headers required (in the example COLUMN1,COLUMN2 etc) with the new OFS. Then take each line, set $1 to $1 to action a change on $0, taking account of the new OFS. Use 1 to print the new line.

Output:

COLUMN1,COLUMN2,COLUMN3,COLUMN4,COLUMN5,COLUMN6,COLUMN7,COLUMN8,
column1,column2,column3,column4,column5,column6,column7,column8,

answered Oct 26, 2020 at 12:37

Raman Sailopal

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2 Comments

Maskiin Over a year ago

Do you mind elaborating more - perhaps using my example? Thanks

Raman Sailopal Over a year ago

I have used your example? I have also assumed the output you need

Shaqil Ismail · Accepted Answer · 2020-10-26 12:24:33Z

0

To add the headers

awk 'BEGIN {print "Column1|Column2|Column3|Column4|Column5|Column6|Column7|Column8"} {print}' table > test1.txt

To add the columns you would like, into the teste.csv

cat test1.txt| awk -F '|' '{print $2, $3, $4, $6, $7}' > teste.csv

answered Oct 26, 2020 at 12:24

Shaqil Ismail

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