Linux Operating System - Debian, Ubuntu, Fedora, Gentoo, Arch

Convert .m4a files to mp3 (AAC to MP3)

ggarron — Sat, 06 Mar 2010 20:20:51 +0000

I have been buying some music on itunes, it comes in AAC (.m4a) format, which is great to use in itunes (I have it on a Windows 7 running over VirtualBox), or to use it in my iPod Touch or iPod shuffle, but if I want to use it in my cell phone (an old one which does not support AAC format) I have to convert it to mp3, I have to also convert it if I plan to use mpg123 which I use a lot.

Well lets go to learn how to convert from AAC to MP3

I will use Arch Linux for this, but you can use any distros, just be sure to install faad and lame.

On an Arch Linux box run:

sudo pacman -Sy faad2 lame

Once installed, run this commands to start converting.

faad file.m4a

This will convert it to wav, and then run:

lame file.wav file.mp3

That is it, you now have an mp3 version of your original aac file.

You may want to make this automatic, for that you can use a small script, this is just an example, you can create a better and more elaborated one.

#!/bin/bash
SAVEIFS=$IFS
IFS=$(echo -en "\n\b")
for f in *
do
  echo "$f"
done
IFS=$SAVEIFS

If you have any suggestions to improve this, use the comments please.

Note to me: Makepkg was unable to build libpng12 package

ggarron — Wed, 24 Feb 2010 13:22:52 +0000

While Trying to install VirtualBox from AUR, and when installing the dependencies, I got this error.

==> Starting build()...
/tmp/yaourt-tmp-keripix/aur-libpng12/libpng12/./PKGBUILD: line 26: patch: command not found
==> ERROR: Build Failed.
Aborting...
Error: Makepkg was unable to build libpng12 package.

It was solved by install base-devel package

sudo pacman -Sy base-devel

So, as a note to me, keep in mind that to install "build" packages from AUR, base-devel package is needed.

How to clear a print queue (spooler) - Linux -

ggarron — Tue, 02 Feb 2010 20:52:09 +0000

It may happen that you have send a real big job to the printer, and then you realize that, you forgot to change the paper size from A4 to letter, or any other scenario where you may need to change something in a document already sent to the printer queue, so now you need to cancel it.

So first lets see the spooler (Printer queue)

lpq

This will list all your jobs sent to the printer.

BJC-250 is ready
Rank    Owner   Job     File(s)                         Total Size
1st     ggarron 248     (stdin)                         0 bytes
2nd     ggarron 249     (stdin)                         0 bytes

Now if you want to stop jobs, you can use the cancel command.

You can cancel only jobs owned by you, or by an specified user (provided that you have the rights to do it).

cancel -u user

This will cancel all jobs belonging to a certain user, but, if you want to cancel all jobs, no matter who owns them use this command.

cancel -a

Use iptables to block access using mac address

ggarron — Mon, 18 Jan 2010 01:51:13 +0000

Iptables, is a great tool to create firewall in Linux, actually it is not only for that, but useful to pre-process or post-process any package of data that arrives to our Linux Operating System machine.

The other day I was needing to block the access to my network using the mac address of a machine, and Iptables come to save my day.

This is my scenario, I have an open Access Point (Do not never do that, always keep your access points closed, using WEP or better WPA, or mac address filtering).

Well, I had it open, and had some neighbours using my Internet, I have a Linux box, with two NICs being my firewall, also working as a DHCP server, and doing NAT, so I just looked at the dhcp file /var/lib/dhcp/dhcpd.leases, and discover the mac address of the intruder, and add the following rule to my firewall

This is the command to use

iptables -t nat -D PREROUTING -m mac --mac-source 00:08:a1:ab:75:d1 -j DROP

That was all, if you want to check how to create a firewall with Iptables, read here, or, here

how to use nslookup

ggarron — Mon, 04 Jan 2010 22:41:40 +0000

I have just wrote a post about how to install nslookup, but what is nslooup?

well, according to wikipedia it is

"nslookup is a computer program used in Windows and Unix to query Domain Name System (DNS) servers to find DNS details, including IP addresses of a particular computer, MX records for a domain and the NS servers of a domain. The name nslookup means "name server lookup". The most common version of the program is included as part of the BIND package. More modern alternatives to nslookup are the "host" and "dig" programs which also ship with BIND. Both nslookup and dig look up nameserver information from /etc/resolv.conf."

This is a very useful tool for system and network administrators, and helps a lot when you are having DNS problems and while troubleshooting them.

There are two ways to use nslookup, directly on the command line, and using its interactive mode.

Command line mode

Enter it in this form

nslooup [server][ip]

[user@myhost ~]$ nslookup www.go2linux.org
Server:         4.2.2.2
Address:        4.2.2.2#53

Non-authoritative answer:
Name:   www.go2linux.org
Address: 97.107.133.237

First it tells you which DNS server it is using, next, it gives you the information it got from that server, giving you the IP address of the server www.go2linux.org

In the interactive mode you have more options, for example.

[ggarron@myhost ~]$ nslookup
> set type=mx
> gmail.com 
Server:         200.87.61.83
Address:        200.87.61.83#53

Non-authoritative answer:
gmail.com       mail exchanger = 40 alt4.gmail-smtp-in.l.google.com.
gmail.com       mail exchanger = 5 gmail-smtp-in.l.google.com.
gmail.com       mail exchanger = 10 alt1.gmail-smtp-in.l.google.com.
gmail.com       mail exchanger = 20 alt2.gmail-smtp-in.l.google.com.
gmail.com       mail exchanger = 30 alt3.gmail-smtp-in.l.google.com.

Authoritative answers can be found from:
gmail.com       nameserver = ns1.google.com.
gmail.com       nameserver = ns2.google.com.
gmail.com       nameserver = ns3.google.com.
gmail.com       nameserver = ns4.google.com.
ns1.google.com  internet address = 216.239.32.10
ns2.google.com  internet address = 216.239.34.10
ns3.google.com  internet address = 216.239.36.10
ns4.google.com  internet address = 216.239.38.10

As you can see, I have typed set type=MX which tells nslookup to inform about Mail eXchange servers, instead of the A records.

You can use set type=NS or with any other of the valid records in DNS, such as CNAME, A, NS, MX, etc.

read the man page of nslookup, and you will get more info about it.

How to install nslookup - Arch Linux

ggarron — Mon, 04 Jan 2010 20:28:28 +0000

If you work with Ubuntu, Debian or Fedora, as soon as you have your default installation, you will probable have nslookup utility installed, but, if you are like me, working on Arch Linux, you will have to install it.

Just enter this.

sudo pacman -S dnsutils

And you will nslookup and other dns utilities ready to run.

How to rebuild vboxdrv on Arch Linux

ggarron — Sat, 02 Jan 2010 17:49:58 +0000

Everytime I upgrade my kernel on Arch Linux, VirtualBox stops working, and everytime, I can't remember the command to rebuild it.

So I am copying here how to do it, so I can come and read it.

---------------------------------------------------------------------------
 IMPORTANT NOTES:

- Run "vbox_build_module" as root every time your kernel is upgraded, to
  compile the module for the new kernel version.
- Add your user to the vboxusers group:
     gpasswd -a USERNAME vboxusers
- Add "vboxdrv" to the MODULES array in your "/etc/rc.conf"
- Add "vboxnetflt" to MODULES if you want Host Interface networking.
- Add "vboxnetadp" to MODULES if you want Host-Only networking.
- If USB does not work for you out-of-the-box, add the following line
  to "/etc/fstab":
     none /proc/bus/usb usbfs auto,busgid=108,busmode=0775,devgid=108,devmode=0664 0 0
---------------------------------------------------------------------------

Hope this may also be useful for anyone finding it on google.

Error opening library libdiscid.so.0

ggarron — Mon, 28 Dec 2009 03:11:28 +0000

If you have installed Picard in Arch Linux, and you try to explore the CD "CD Lookup", you may get an error like this:

Error While reading CD

Error opening library: libdiscid.so.0 cannot open shared object file: No such file or directory

That is because, you may have not installed libdiscid.so.O, so go ahead and install it from yaour.

yaourt libdisc

You will get something like this:

1 aur/libdiscid 0.2.2-2 (47)
    A Library for creating MusicBrainz DiscIDs
==>  Enter n° (separated by blanks, or a range) of packages to be installed
==>   ----------------------------------------------
==>

Select the package, and yaourt will install it, from there the error will not appear anymore.

If you are installing picard on Ubuntu or Fedora or Debian you will not have this problem, as the library will be installed automatically.

Picard Tagger - Automatically tag your mp3 music files

ggarron — Sat, 26 Dec 2009 15:26:47 +0000

I do not have a very big mp3 music files collection, just 2 to 3 gigs of them, but I have made it over the years, and some of the original CDs are missed, so I can not import them again.

I am using an iPod Touch and iTunes to hear my collection, and all the music I have bought from itunes is nicely classified, and I have the Album picture also available, but with my old imported music I do not have it, because the tags are not properly set.

I have stumbled into this great application, which is written in phyton, and therefore is available for Linux, I am actually using Arch Linux and for this distro it is available through community.

So just enter:

yaourt picard

And you will get this:

1 community/picard 0.12.1-1
     Next generation MusicBrainz tagging application (QT4 interface)
2 aur/picard-bzr 978-2 (12)
    Next generation MusicBrainz tagging application (bzr version)
3 aur/picard-plugins 0.12-3 (50)
    Plugins for MusicBrainz Picard
4 aur/picard-plugins-lastfmplus 0.12-2 (3)
    LastFMPlus Plugin for MusicBrainz Picard
5 aur/picard-plugins-search 0.12-1 (23)
    search plugins for MusicBrainz Picard
6 aur/picard-qt 0.9.0beta1-2 (Out of Date) (40)
    Next generation MusicBrainz tagging application (QT4 interface)
==>  Enter n° (separated by blanks, or a range) of packages to be installed
==>   ----------------------------------------------
==>

Select number 1 and install the community version, if you do not have yaourt installed you can use pacman instead.

Once installed just run it, from the menu, or from a console

picard &

You will see a screen like this:

From the menu Options -> Options select Moving files, you will get a screen like the one below.

Enter the folder where you want to be copied your new tagged files, I usally use /tmp/ as from there I then import them to iTunes (I use windows in a Virtual Box for iTunes)

Now just add files or folders you may want to analyze and click on scan, you will have their tags updated, after it finished, if you are satisfied with the results, click on save to have a copy of your mp3, with the right tags in your /tmp/ folder.

You can now import it to iTunes and use it on your iPod or iPhone, or use it as you wish.

For more info about picard, go to Musicbrainz

Putty for Nokia Symbian S60

ggarron — Sat, 19 Dec 2009 18:10:07 +0000

If you are usually on the move, and you need quick access to your Linux server, you may buy a Nokia Symbian phone, E-series, N-series, and others like 6120 classic are useful, and you can then install Putty for Symbian on it and from there access to your Linux box.

Here are some screenshots of Putty for Symbian in action.

You can create different profiles, in order to save time accesing the same servers, some other features, are: You can change fonts, You can use full screen, You can create a log file, for more info about features, download putty for symbian manual in PDF format