Extract Lines when Column K is empty with AWK/Perl

Posted by neversaint on Stack Overflow See other posts from Stack Overflow or by neversaint
Published on 2010-05-25T06:24:04Z Indexed on 2010/05/25 6:31 UTC
Read the original article Hit count: 245

Filed under:

linux

|

perl

|

unix

|

awk

I have data that looks like this:

foo 78 xxx
bar    yyy
qux 99 zzz
xuq    xyz

They are tab delimited. How can I extract lines where column 2 is empty, yielding

bar    yyy
xuq    xyz

I tried this but doesn't seem to work:

awk '$2==""' myfile.txt

© Stack Overflow or respective owner

Related posts about linux

apt-get install and update fail

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I've got a problem with apt-get update and apt-get install ... commands . every time update or installing fails and errors are : Get:1 http://dl.google.com stable Release.gpg [198B] Ign http://dl.google.com/linux/chrome/deb/ stable/main Translation-en_US Get:2 http://dl… >>> More
kernel module compiling error

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
sh@ubuntu:/home/ccpp/helloworld$ make gcc-4.6 -O2 -DMODULE -D_KERNEL_ -W -Wall -Wstrict-prototypes -Wmissing-prototypes -isystem /lib/modules/`uname -r`/build/include -c -o hello-1.o hello-1.c hello-1.c:4:0: warning: "MODULE" redefined [enabled by default] <command-line>:0:0: note: this is… >>> More
Build-Essentials installation failing

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I am having trouble accessing the several critical header files that show to be a part of the build process. The "Ubuntu Software Center" shows "Build Essentials" as installed: Next I did the following two commands, which did not improve the problem: ~$ sudo apt-get install build-essential [sudo]… >>> More
Updating Debian kernel

as seen on Super User - Search for 'Super User'
I'm trying to update my Debian machine to 2.6.32-46 (which is the new stable). However, after doing apt-get update my apt-cache search linux-image shows me: linux-headers-2.6.32-5-486 - Header files for Linux 2.6.32-5-486 linux-headers-2.6.32-5-686-bigmem - Header files for Linux 2.6.32-5-686-bigmem linux-headers-2… >>> More
Serial connection over a single USB cable (Windows to linux, or linux to linux)

as seen on Server Fault - Search for 'Server Fault'
I'm helping out with a project for an embedded device that only has USB and no serial. This device is running Linux. These days, when we need to connect to a serial port on a device we typically use a USB to serial adapter (on something like a phone system or a load balancing device, etc). I would… >>> More

Related posts about perl

Munin on Centos 6 - missing perl MODULE_COMPAT_5.8.8

as seen on Server Fault - Search for 'Server Fault'
I'm trying to install Munin on a new VPS through yum install munin but I keep getting an error about a missing perl module: Requires: perl(:MODULE_COMPAT_5.8.8). This is the perl version currently installed: v5.10.1. I've searched all around and still haven't found a solution for this. Here's the… >>> More
Pain removing a perl rootkit

as seen on Server Fault - Search for 'Server Fault'
So, we host a geoservice webserver thing at the office. Someone apparently broke into this box (probably via ftp or ssh), and put some kind of irc-managed rootkit thing. Now I'm trying to clean the whole thing up, I found the process pid who tries to connect via irc, but i can't figure out who's… >>> More
How To Avoid a Perl script calling an Another Perl Script

as seen on Stack Overflow - Search for 'Stack Overflow'
Hello, i am calling a perl script client.pl from a main script to capture the output of client.pl in @output. is there anyway to avoid the use of these two files so i can use the output of client.pl in main.pl itself here is my code.... main.pl ======= my @output = readpipe("client.pl"); client… >>> More
Perl :how to sort dates in perl

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, How can I sort the dates in perl. my @dates = ( "02/11/2009" , "12/20/2001" , "11/21/2010" ) ; I have above dates in my array . How can I sort those dates... ? My date format is dd/mm/YYYY. >>> More
please suggest a perl book exclusively for perl programs

as seen on Stack Overflow - Search for 'Stack Overflow'
I want tha name of a perl book for only PERL PROGRAMS. The reason behind is I want to improve my programming skill in perl >>> More