Skip to main content

AWK : Printing columns


In awk each column can be represented by $n , where n can be any number 0,1,2,3 etc.We must specify the delimited of the fields in the command. By default a space or any amount of consecutive spaces is considered as delimiter.

1. To print the column 1 and 4 of the below data in awk

> cat sample.txt 

Tom 1990 IT 98
Joseph 1988 Mechanical 80
Mary 1991 Electronics 95

> awk '{print $1, $4 } ' sample.txt

Tom 98
Joseph 80
Mary 95

2. To print the entire column of the text 

> awk 'print{$0}' sample.txt

Tom 1990 IT 98
Joseph 1988 Mechanical 80
Mary 1991 Electronics 95

3. To print add a text along with column values - 

In the below example we are going to add text "Name:" in front of column 1 , and "Marks:" before column 4.

> awk '{print "Name:"$1," Marks:"$4}' sample.txt

Name:Tom  Marks:98
Name:Joseph  Marks:80
Name:Mary  Marks:95

4. To print the number of words in each line we can use NF parameter .Here each line has four fields.

> awk '{print $0",",NF}' sample.txt

Tom 1990 IT 98, 4
Joseph 1988 Mechanical 80, 4
Mary 1991 Electronics 95, 4

5. If the file is having a different delimiter , say comma(,) , then we have to specify that in awk command to separate the column.

> cat sample2.txt

Tom,1990,IT,98
Joseph,1988,Mechanical,80
Mary,1991,Electronics,95

> awk -F"," '{print $1,$4}' sample2.txt

Tom 98
Joseph 80
Mary 95


Comments

Popular posts from this blog

Excel : How to pad zeros

Today I got a requirement to format the number in excel cell - to left pad number with zeros.i find the following function very useful to do it. In case one to make the number left padded with "0" s give the formula =TEXT(A1,"0000") In case two even more enhanced form to make it left padded with "0" and add two decimal places give the formula as =TEXT(A2,"0000.00")

Mount an iso image in ubuntu using no GUI

We can easily mount an iso image file in our system to a directory in linux.We need not require an GUI application to do this.It is easy to do from the terminal itself. We use the mount command for that. The steps are as follows  1. Open the terminal in ubuntu (Shortcut press ctrl+Alt+t) 2. Create a directory to mount the iso image              $sudo mkdir /media/myimage 3. Then type the following command     $sudo modprobe loop 4.After that go to the location of the iso image file and type     $sudo mount /media/myimage -t iso9660 -0 loop     The iso file is mounted to the specified directory To unmount it give the command   sudo unmount /media/myimage That all.Cool isn't! sudo modprobe loop will loads the module for loopback file system iso9660 is the file system used by CD-ROM -t specify the file system type -o loop additional option used by a loopback filesystem

How to add fonts in Ubuntu?

To add fonts like Times New Roman , Ariel etc in Ubuntu do the following. 1. open ubuntu Software Center  2. Searh fo r  ttf-mscorefonts   in search  bar. 3. Install the item listing in the page. Now you can use new fonts in ubuntu.