$ sudo visudo
>>> /etc/sudoers: syntax error near line 28 <<<
sudo: parse error in /etc/sudoers near line 28
sudo: no valid sudoers sources found, quitting
On a modern Ubuntu system (and many other GNU/Linux distributions), fixing a corrupted sudoers file is actually quite easy, and doesn’t require rebooting, using a live CD, or physical access to the machine.
To do this via SSH, log in to the machine and run the command pkexec visudo. If you have physical access to the machine, SSH is unnecessary; just open a Terminal window and run that pkexec command. Lire la suite…
Improvement of the command “Find Duplicate Files (based on size first, then MD5 hash)” when searching for duplicate files in a directory containing a subversion working copy. This way the (multiple dupicates) in the meta-information directories are ignored.
Can easily be adopted for other VCS as well. For CVS i.e. change “.svn” into “.csv”:
Finds duplicates based on MD5 sum. Compares only files with the same size. Performance improvements on:
find -not -empty -type f -printf "%s\n" | sort -rn | uniq -d | xargs -I{} -n1 find -type f -size {}c -print0 | xargs -0 md5sum | sort | uniq -w32 --all-repeated=separateThe new version takes around 3 seconds where the old version took around 17 minutes. The bottle neck in the old command was the second find. It searches for the files with the specified file size. The new version keeps the file path and size from the beginning.
find . -type f -exec md5 '{}' ';' | sort | uniq -f 3 -d | sed -e "s/.*(\(.*\)).*/\1/"
This works on Mac OS X using the `md5` command instead of `md5sum`, which works similarly, but has a different output format. Note that this only prints the name of the duplicates, not the original file. This is handy because you can add `| xargs rm` to the end of the command to delete all the duplicates while leaving the original.
# Modify this file accordingly for your specific requirement.
# http://www.thegeekstuff.com
# 1. Delete all existing rules
iptables -F
# 2. Set default chain policies
iptables -P INPUT DROP
iptables -P FORWARD DROP
iptables -P OUTPUT DROP
# 3. Block a specific ip-address
#BLOCK_THIS_IP="x.x.x.x"
#iptables -A INPUT -s "$BLOCK_THIS_IP" -j DROP
Lire la suite...
(D)DoS Deflate is a lightweight bash shell script designed to assist in the process of blocking a denial of service attack. It utilizes the command below to create a list of IP addresses connected to the server, along with their total number of connections. It is one of the simplest and easiest to install solutions at the software level.
IP addresses with over a pre-configured number of connections are automatically blocked in the server’s firewall, which can be direct iptables or Advanced Policy Firewall (APF). (We highly recommend that you use APF on your server in general, but deflate will work without it.)
Notable Features
It is possible to whitelist IP addresses, via /usr/local/ddos/ignore.ip.list.