12 Jun 2009 Replace specific HTML tags using sed and regular expression
In this post I would like to replace all <embed> HTML tags in a HTML file with a <strong> tag.
# sed -e 's/<embed[^>]*>/<strong>/g' filename.html > newfile.html
And if you would like to remove the <embed> tag altogether
# sed -e 's/<embed[^>]*>//g' filename.html > newfile.html
To remove all HTML tags in a file
# sed -e 's/<[^>]*>//g' filename.html > newfile.html
The result file newfile.html is now without any < HTML tags >.
Tags: html, regexp, replace, sed
Posted by Hans-Henry Jakobsen
21 Jan 2009 IP address change notifier script
This is a simple bash script that is run by crontab every 5 minutes on a linux box.
It e-mails me the new address when a change of IP address is detected.
The script (ipchangemail.sh)
#!/bin/bash
# Check if IP-address has changed. If a change has occured, mail me the new address
# Add the following line to crontab if you would like it to be run every 5 minutes:
# */5 * * * * ./ipchangemail.sh
# The network interface I want to monitor
NET_INTERFACE=eth0
# File to keep the latest IP address
IP_FILE=myip.txt
# Mail to this address when a change occur
MAILTO=mail@example.com
# Read the previous IP address from file
source $IP_FILE
CURRENT_IP=`/sbin/ifconfig $NET_INTERFACE | sed -n "/inet addr:.*255.255.25[0-5].[0-9]/{s/.*inet addr://; s/ .*//; p}"`
if [ "$CURRENT_IP" != "$OLD_IP" ]
then
# Send email about address change
`echo "New IP address detected: $CURRENT_IP" | mail -s "New IP address" $MAILTO`
# Write new address to file
`echo "OLD_IP=$CURRENT_IP" > $IP_FILE`
fi
The script can be downloaded here.
Tags: bash, ifconfig, mail, sed
Posted by Hans-Henry Jakobsen
21 Feb 2008 Apache web connections pr hour
This is a bash oneliner to show Apache web connections pr hour. It lists up the IPs that has accessed your webserver and the amount og accesses.
# cat /var/log/apache2/access_log_pario.no | grep "21/Jan/2008:.." | awk {' print $4":"$1 '} | sed 's/\[//g' | awk -F : {' print $1":"$2"\t\t"$5 '} | sort | uniq -c
Example output
37 21/Jan/2008:00 192.168.0.10
This shows that I had 37 hits from 00:00 – 01:00 in 20th February 2008.
Tags: Apache, awk, bash, grep, sed
Posted by Hans-Henry Jakobsen
04 Dec 2007 Strip the kernel to contain only needed modules
This is a great page with som nice bash scripts describing how to remove unwanted modules from your kernel.
Tags: bash, cut, grep, kernel, lsmod, modinfo, sed, xargs
Posted by Hans-Henry Jakobsen
25 Oct 2007 Using TCP Wrappers to deny daemon access in specified hours
By doing the following you can deny certain daemons to be available in specified hours by using hosts.allow and hosts.deny.
In my example I will be using the vsftpd daemon by adding
tcp_wrapper=YES
in /etc/vsftpd.conf.
Make sure that your private network has access all the time by adding this in /etc/hosts.allow
vsftpd: 192.168.0.
Enables access to the whole subnet.
Next you create a /etc/cron.d/vsftpd file
0 16 * * 1-5 root perl -i -p -e s/innhold//ig /etc/hosts.deny 0 8 * * 1-5 root echo "vsfdpt:ALL >> /etc/hosts.deny
Reload the cron daemon and you’re good to go.
The above example will deny all addresses, except those specified in hosts.allow, between 08:00 and 16:00 Monday to Friday and clear the block at other times.
Posted by Hans-Henry Jakobsen
