Body of Knowledge

some sed examples

Sun, 27 Dec 2009 22:16:03 +0000

Sed stands for “stream editor” and parses text file to apply textual transformations. It evolved as the natural successor of grep.

Below some examples of commands:
http://sed.sourceforge.net/sed1line.txt

migration from Windows to Linux (Ubuntu)

Sun, 19 Jul 2009 17:21:00 +0000

If you want to give Linux a try here goes a list of replacements for the usual stuff in windows:

http://www.linuxrsp.ru/win-lin-soft/table-eng.html

If you dislike the replacements you can always use the windows version with wine - windows emulator:
http://appdb.winehq.org

Big-IP v4 redirect

Mon, 22 Jun 2009 23:42:24 +0000

If you want to generate an unconditional redirect from siteA to siteB, just write this:

if (http_host starts_with “www.siteA.com”) {
redirect to http://www.siteB.com:%p/%u“

}

Where:
- %p stands for the port.
- %u stands for the url path.

fc bash command

Fri, 12 Jun 2009 23:52:35 +0000

“fc” will bring the last command typed into an editor, “vi” if that’s the default editor. Of course you can specify a different editor by using the -e switch as follows:
$ fc -e emacs
To list last few commands, type:
$ fc -l
For the last 10 commands it will be:
$ fc -l -10

acl on ext2/ext3

Fri, 12 Jun 2009 23:39:39 +0000

Ever wandered how to have a full file ACL on your Linux filesystem instead of the usual user:password:others?

apt-get install libattr1 libacl1 acl

setfacl
getfacl
Interesting links:

http://www.adelux.fr/libre/howto/en/samba_ext3_acl

mirror/download a website

Sun, 20 Jan 2008 23:36:50 +0000

If you need for some reason to download a full website, wget is a nice tool to accomplish this.
With “man wget” you can get a pretty good idea of all available features. I heard there is also a wget version for windows.

Let us examine an example:

-m stands for mirroring
-k and -K convert the page with local links
-E to convert to an html suffix
–random-wait to add a random waiting period between requests

$ wget -m -E -k -K -w 1 --random-wait -o logfile http://website_uri/path

Disable directory browsing in apache

Sun, 20 Jan 2008 23:35:12 +0000

You can disable directory browsing at several levels like everything else.

In order to do that:

Edit either the http.conf or a specific .conf file or the .htaccess file.
If exists, look for “Option Indexes”
Replace it or create a new line with “Options -Indexes”

WPA 1 on Ubuntu 7.10 Gutsy

Thu, 08 Nov 2007 02:00:05 +0000

After trying the gnome network configuration tool with little success, I tried the hardcore version, changing by hand the /etc/network/interfaces file again with little success.

First search for your AP:

$ iwlist eth1 scanning

If you have a working wireless network adapter (eth1) and your AP in range, your configuration file should look something like this:

auto eth1
iface eth1 inet dhcp
wpa-driver wext
wpa-ssid SSID
wpa-ap-scan 1
wpa-proto WPA
wpa-pairwise TKIP
wpa-group TKIP
wpa-key-mgmt WPA-PSK
wpa-psk XXXXXXXXXXXXXXXXXXXXf4b3cff05d8ebf483435050268bxxxxxxxxxx

Your key for wpa-psk can be generated using:

 sudo wpa_passphrase SSID "passphrase"

So what can actually make you nuts is that if you used an hidden SSID, it will not work until you make the SSID visible once… and then you can go back into being hidden again.

Another way is to use the command iwconfig:

sudo iwconfig eth1 essid "hidden_ssid"

redhat rpms for very old versions

Tue, 23 Oct 2007 16:14:36 +0000

You can find it here:

http://rpmfind.net/linux/rpm2html/search.php?query=&submit=Search+…&system=&arch=

check the latest kernel version available

Tue, 21 Aug 2007 23:14:41 +0000

In order to check the latest kernel version available just do this:

$ finger @kernel.org

And get an output similar to:

[kernel.org]
The latest stable version of the Linux kernel is:           2.6.22.4
The latest prepatch for the stable Linux kernel tree is:    2.6.23-rc3
The latest snapshot for the stable Linux kernel tree is:    2.6.23-rc3-git4
The latest 2.4 version of the Linux kernel is:              2.4.35.1
The latest 2.2 version of the Linux kernel is:              2.2.26
The latest prepatch for the 2.2 Linux kernel tree is:       2.2.27-rc2
The latest -mm patch to the stable Linux kernels is:        2.6.23-rc2-mm2