Mar 3

[Bash] Script for monitoring content of website

Bash bash, monitoring Add Comment (0)

Imagine that you are waiting for marks from exam. Lecturer is going to publish them on his website, but you don’t know when.
I’ve created following script, because I don’t like pressing F5 for hours
You have to provide address of website, and if website changes, script will open firefox and show notification.

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#!/bin/sh
# Wojtek Jamrozy www.wojtekrj.net
 
if [ $# != 1 ]; then
	echo "usage: $0 <url of website> "
	exit 1
fi
hash=`wget -q -O - $1 | md5sum`
 
while [ 1 ]; do
	if [ "`wget -q -O - $1 | md5sum`" != "$hash" ]; then
		firefox $1
		notify-send "Change on the website $1"
		exit 0
	fi
	echo "Nothing has changed"
	sleep 120
done

Sep 21

[Bash,Linux] Very fast disk shredding/data erasure script

Bash, Linux bash, data erasure, disk shreding, Linux Add Comment (0)

Before I have setted up my encrypted partitions I had to fill them with random sequention of data.
I’ve noticed that dd if=/dev/urandom of=DEVICE is very slow. It has 3-4 MB/second on my computer.
I wanted to make it faster. Here is my solution:
1. Create in tmpfs located in RAM memory large file (about 100 MB) made of pseudo-random sequence (/dev/urandom).
2. Write this file from memory sequentially to the disk.
Speed of this approach is even 34 MB/s – 10 times faster!!.
Unfortunately, this aproach might not be as secure as dd if=/dev/urandom of=DEVICE
Before you do anything backup your data and be sure what are you doing!!!
My implementation: Read More

Sep 12

[Linux] Random password generator

Bash, Linux, Ubuntu password generator Add Comment (0)

Here is a script for generating random alphanumeric passwords:

#!/bin/bash 
# passwords.sh  
if [ $# != 2 ]; then
	echo "usage: $0 <length of passwords> <number of passwords> "
	exit 1
fi
tr -cd '[:graph:]' < /dev/urandom | fold -w $1 | head -$2

Aug 30

[Bash] How to show information about dd progress / statistics

Bash bash, dd, kill, script Add Comment (0)

dd is a great tool for low-level copying and conversion of raw data. It can be also used for data erasure. Unfortunately, it doesn’t show any information about progress of copying.
Here is my little, but useful script:

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#!/bin/bash 
# dd.sh Author: Wojtek Jamrozy (www.wojtekrj.net)
 
dd $* & pid=$!
sleep 10
 
while [ -e "/proc/$pid" ] ; do
	kill -USR1 $pid 
	sleep 10
done

Read More

Aug 11

[Ubuntu] Packages auto-purging script

Bash, Ubuntu bash, packages, purging, Ubuntu Add Comment (0)

Here is my script for auto-purging of removed packages (the script deletes remaining configuration files of package) in Ubuntu:

#!/bin/sh
for i in `dpkg -l | grep ^rc | cut -f 3 -d ' '`
do
    dpkg -P $i;
done

Read More