FAQ

A collection of Frequently Asked Questions, Help, Hacks, Tips and more

Awk Floating Point Number Addition Results Are Unexpected

last updated in Categories , , ,

I am using awk to grep ‘foo’ from a text file and cacluate sum of field # 7. But, result is rounded to an integer. I need exact result such as 385858.66 and not 385858 using the following command:

grep ‘foo’ 2012-2013.txt | awk ‘BEGIN{ sum=0.0}{ sub(“,”,””,$7); sum +=$7}END{ print “$” sum}’
$682444

I want $682444.57 as output. How can I force “awk” to do floating point math?

Awk Find And Replace Fields Values

last updated in Categories , , ,

I have a data as follows :

foo bar 12,300.50
foo bar 2,300.50
abc xyz 1,22,300.50

How do I replace all , from 3rd field using awk and pass output to bc -l in the following format to get sum of all numbers:
12300.50+2300.50+1,22,300.50

Linux / Unix: curl Command Pass Host Headers

last updated in Categories , ,

How do I send a header to my Web server (such as Nginx / Lighttpd / Apache / ISS) on a Apple OS X or Unix or Linux based system using a curl command line option for testing and debugging my web apps or server nodes behind a load balancer?

Linux AWS: Find And Delete All Files Securely So That No One Can Recover It Ever

last updated in Categories , , ,

I‘m currently using Amazon EBS block level storage volumes for use with Amazon EC2 instances powered by Red Hat Enterprise Linux. This volume stores critical webapp and user data. We are moving out to another cloud provider. How do I find files such as *.logs, *.php, *.gz and few other file patterns and securely delete them so that no one can recover it ever?