quick file copy (without ftp/scp)

This is for quick copy only, where you don't want to setup any ftp or scp server
and have the machines in same network

## say we have two hosts: alpha & beta
##  need to copy: file-big.tgz
## linux util: nc

on host: alpha
$ cat file-big.tgz | nc -v -l 3334


now get the file on host:beta
$ nc  -v  alpha 3334   > file-from-alpha-file-big.tgz


voila, we have the file on host beta...

milliseconds to date

Most of the java apps use milliseconds, here is bash date for getting the date for the same


## Current system date

$ date

Tue Jun  2 08:07:57 UTC 2015

## Epoch system date

$ date +"%s"

1433232485

## Milliseconds for the date

$ date +"%s%3N"

1433232489392

## Last 3 digits are for millisecs, so put decimal point and you get the get

$ date -d @"1433232489.392"

Tue Jun  2 08:08:09 UTC 2015

## or strip of Last 3 digits

$ date -d @"1433232489"

Tue Jun  2 08:08:09 UTC 2015

script for reading file or stream

I often wanted to pass the file to a pipeline some command, and also if the file is parameter to command it should accept


Voila!!

here is 'stream.sh'

#!/bin/bash

file=${1:--}

cat $file 

Usage and output

$ ./stream.sh underSTANDING.txt 

If you understand, say "understand".

If you don't understand, say "don't understand".

But if you understand and say "don't understand".

How do I understand that you understand? Understand!

$ cat underSTANDING.txt | ./stream.sh 

If you understand, say "understand".

If you don't understand, say "don't understand".

But if you understand and say "don't understand".

How do I understand that you understand? Understand!

$ ./stream.sh < underSTANDING.txt 

If you understand, say "understand".

If you don't understand, say "don't understand".

But if you understand and say "don't understand".

How do I understand that you understand? Understand!

bytes to gb/tb conversion

Often had to go to websites to do the bytes to KB.. TB.. GB conversions
here is the quick script for handy use

#!/bin/bash

# Give numeric value, which is in bytes

# will show all possible conversions 

call_bc() {

n1=$1

n2=$2

echo "scale=4; $n1/($n2)" |bc

}

nm=$1

pw=$2

pn=""

k_ilo=1024;

m_ega=$k_ilo*$k_ilo;

g_iga=$m_ega*$k_ilo;

t_era=$g_iga*$k_ilo;

p_eta=$t_era*$k_ilo;

[ -z "$nm" ] && exit

echo  "B: "$nm

for i in K M G T P; do

case $i in

K)pn=$k_ilo;;

M) let pn=$m_ega;;

G) let pn=$g_iga;;

T) let pn=$t_era;;

P) let pn=$p_eta;;

esac

echo -n "$i: "; call_bc $nm $pn

done

Usage and output

$ ./convert.sh 74274576

B: 74274576

K: 72533.7656

M: 70.8337

G: .0691

T: 0

P: 0