AWK: Print Column – Change Field Separator – Linux Bash

The awk is a powerful Linux command line tool, that can process the input data as columns.

In the following note i will show how to print columns by numbers – first, second, last, multiple columns etc.

I will show how to change the default field separator in awk.

At the end of this article i will also show how to print or exclude specific columns or even ranges of columns using awk.

Cool Tip: Print lines of a file between two matching patterns using awk or sed! Read more →

AWK: Print Columns by Number

Print the all columns:

$ awk '{print $0}' FILE

Print the first column:

$ awk '{print $1}' FILE

Print the second column:

$ awk '{print $2}' FILE

Print the last column:

$ awk '{print $NF}' FILE

Print multiple columns (the first and the third columns):

$ awk '{print $1 $3}' FILE

Cool Tip: Add character to the beginning or to the end of each line of a file using awk or sed! Read more →

AWK: Change Field Separator

The field separator can be either a single character or a regular expression.

It controls the way awk splits an input record into the fields.

By default, awk uses both space and tab characters as the field separator.

You can tell awk how fields are separated using the -F option on the command line.

Use , (comma) as a field separator and print the first field:

$ awk -F "," '{print $1}' FILE

Use : (colon) as a field separator and print the second field:

$ awk -F ":" '{print $2}' FILE

AWK: Exclude Columns

Print all the other columns but not the third one:

$ awk '{$3=""; print $0}' FILE

Print all the other columns but not the first and the second ones:

$ awk '{$1=$2=""; print $0}' FILE

Cool Tip: Remove blank lines from a file using grep, tr, sed or awk! Read more →

AWK: Print or Exclude a Range of Columns

Print a range of columns from the first till the fourth:

$ awk -v f=2 -v t=4 '{for(i=f;i<=t;i++) printf("%s%s",$i,(i==t)?"\n":OFS)}' FILE

Exclude a column range from the second till the fourth and print the rest:

$ awk -v f=2 -v t=4 '{for(i=1;i<=NF;i++)if(i>=f&&i<=t)continue;else printf("%s%s",$i,(i!=NF)?OFS:ORS)}' FILE