Archive for ‘CLI’ Category

Terminal Tip: Finding information about a mp3 audio file…

datePosted on 13:24, October 19th, 2010 by Many Ayromlou

Here is a quick tip for you OSX command line fans. If you want to find metadata information about a mp3 file use the “afinfo” command. Very quick and scripting friendly. Here is a example:

$ afinfo 08_\ Lily\ Allen\ -\ Fk\ You.mp3 
File:           08_ Lily Allen - Fk You.mp3
File type ID:   MPG3
Data format:     2 ch,  44100 Hz, '.mp3' (0x00000000) 0 bits/channel, 0 bytes/packet, 1152 frames/packet, 0 bytes/frame
                no channel layout.
estimated duration: 215.249 sec
audio bytes: 5167920
audio packets: 8240
audio 9490176 valid frames + 576 priming + 1728 remainder = 9492480
bit rate: 192000 bits per second
packet size upper bound: 1052
maximum packet size: 731
audio data file offset: 32353

Duplicating service settings under OSX Server…

datePosted on 14:17, August 25th, 2010 by Many Ayromlou

This mainly applies to how you deal with a backup DHCP server and it’s configuration, but might also be useful for backing up other service settings. One of the things that kinda bugs me about how some services are configured in OSX Server is the fact that the configurations are stored in the directory. For example, if you have a DHCP server servicing a subnet with a ton of reservations hardcoded in it, there is no way of editing and/or moving the information from the command line (ie: there is no single config file that contains the current configuration) to another server. That’s where the “serveradmin” commandline program comes to rescue. If you have two identical servers (ie: both running the same OSX server version), you can use serveradmin to export the settings from a specific service and then move the file to the new server and import it there. All using the CLI.

  • To Export the settings (in this case the DHCP service):
  • sudo serveradmin settings dhcp > dhcp-config.txt
  • To Import the settings on the other server:
  • sudo serveradmin settings < dhcp-config.txt

MySQL: Transfering users and priviledges to a new server….

datePosted on 15:32, August 19th, 2010 by Many Ayromlou

So this was a great big mystery this morning. How the heck do you transfer the users and their privileges out of a old mysql server and “import” them into a new server. We recently upgraded from OSX 10.4.11 to a couple of spanking new Snow Leopard servers and during the mysql export/import cycle this issue came up. Well the simple answer is…..DON’T USE mysqldump on your mysql DB (you know the default DB that stores all your users and privileges. It’s a bad idea and will probably do more harm than good. Instead use the following procedure:

1) On your old server (the one that has your data/users/tables on it) issue the following command (replace YOUR dbadmin/root username and  password in the 2 appropriate places:

mysql -B -N --user=admin --password=yourpassword -e "SELECT DISTINCT CONCAT('SHOW GRANTS FOR ''', user, '''@''', host, ''';') AS query FROM mysql.user" |mysql --user=admin --password=yourpassword | sed 's/\(GRANT .*\)/\1;/;s/^\(Grants for .*\)/## \1 ##/;/##/{x;p;x;}'

The output of this command is something like this:

## Grants for admin@ ##
## Grants for fabrik@localhost ##
GRANT ALL PRIVILEGES ON `fabrikdb`.* TO 'fabrik'@'localhost' WITH GRANT OPTION;
## Grants for nerdlogger@localhost ##
GRANT ALL PRIVILEGES ON `nerdlogger`.* TO 'nerdlogger'@'localhost' WITH GRANT OPTION;
## Grants for research@localhost ##
GRANT SELECT, INSERT, UPDATE, DELETE, CREATE, DROP, INDEX, ALTER ON `research`.* TO 'research'@'localhost';
## Grants for admin@localhost ##
## Grants for root@server.domain ##

2) Now you’re ready to selectively cut and paste the appropriate users and associated grant into a new mysql session (which you have to open) on the new server.


ASCII Art for all your needs :-)…..

datePosted on 22:33, November 10th, 2009 by Many Ayromlou

Yep, a whole archive of ASCII Art, brought to you by Christopher A. Johnson……Ahhh, just like heaven….

                       ?$""`?i           z'
                       `M  .@"          x"
                       'Z :#"  .   .    f 8M
                       '&H?`  :$f U8   <  MP   x#'
                       d#`    XM  $5.  $  M' xM"
                     .!">     @  'f`$L:M  R.@!`
                    +`  >     R  X  "NXF  R"*L
                        k    'f  M   "$$ :E  5.
                        %    `~  "    `  'K  'M
                            .uH          'E   `h
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                   'E9F  uf"          ,     ,
                     9h+"   $M    eH. 8b. .8    .....
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                     >      K.zM `%M'   9'    Xf   .f
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                    t                   M     Mx~
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                      .z""   ?
                    M#`      9     ,     ,
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                 4;    $k      /         dH    $f
                 'X   ;$$     z  .       MR   :$
                  R   M$$,   :  d9b      M'   tM
                  M:  #'$L  ;' M `8      X    MR
                  `$;t' $F  # X ,oR      t    Q;
                   $$@  R$ H :RP' $b     X    @'
                   9$E  @Bd' $'   ?X     ;    W
                   `M'  `$M d$    `E    ;.o* :R   ..
                    `    '  "'     '    @'   '$o*"' 

Fix Ctrl-Alt-Backspace problem with Ubuntu 9.10+

datePosted on 13:58, October 31st, 2009 by Many Ayromlou

Downloaded and installed 9.10 yesterday and what do you know, someone decided to take away Ctrl-Alt-Backspace — or what I call “Three Finger Salute for Linux”. Whhhaaattt!!!!

How the heck are you supposed to kill and restart X without that…..A coworker suggested Alt-PrintScreen-K, but that just restarts GDM, not really useful when X decides to go south. Damit!!
The reason given on Ubuntu wiki is that “This is due to the fact that DontZap is no longer an option in the X server and has become an option in XKB instead.”
Well, fear not, whoever disabled it also created a easy way to reenable it again. Here is what you do:

  • In Gnome (Ubuntu):

    * Get to the System->Preferences->Keyboard menu.
    * Select the "Layouts" tab and click on the "Layout Options" button.
    * Then select "Key sequence to kill the X server" and enable "Control + Alt + Backspace".
  • In KDE (Kubuntu):
    * Launch "systemsettings"
    * Select "Regional & Language".
    * Select "Keyboard Layout".
    * Click on "Enable keyboard layouts" (in the Layout tab).
    * Select the "Advanced" tab. Then select "Key sequence to kill the X server" and enable "Control + Alt + Backspace".
  • Using Command-Line:
    You can type the following command to enable Zapping immediately.

    setxkbmap -option terminate:ctrl_alt_bksp

    If you're happy with the new behaviour you can add that command to your ~/.xinitrc in order to make the change permanent.
  • Using HAL:
    You can add the following line in /usr/share/hal/fdi/policy/10osvendor/10-x11-input.fdi (inside the <match key="info.capabilities" contains="input.keys"> section):

    <merge key="input.xkb.options" type="string">terminate:ctrl_alt_bksp</merge>

ASCII Art at it’s finest…..

datePosted on 12:14, October 19th, 2009 by Many Ayromlou

Not sure if this has already been mentioned somewhere…..It’s pretty old, but I happen to come across it today. It’s a great rendition of everyone’s favorite space opera done by Simon Jansen in ASCII. Telenetification (is that even a word?) by Snore, with improvements by Mike Edwards. Anyways, use the following command, sit back and enjoy…..Star Wars in all its ASCII glory :-)

If you don’t know how to telnet, click here to see it in your browser.

gksudo: Or how this old dog learned new tricks :-)

datePosted on 12:19, September 28th, 2009 by Many Ayromlou

Okay if you know about gksudo, fine. I just found out about it a little while back when I was trying to run ethereal. You see under Ubuntu (and a lot of other Linux distros) the concept of root user has been removed. There is no root (well there is, but you can’t access it), unless you specifically modify your system to activate it. That’s fine (most of the time), since you can use sudo to accomplish almost anything as the administrator. One thing that doesn’t work properly are the graphical applications that need root access. So here is where gksudo comes to rescue. In the case of ethereal I would issue the following command to get it to prompt me for sudo and run as root user:
gksudo ethereal
So next time you get tempted to open up that root account on your Ubuntu install, don’t, use gksudo and get those gui apps running as root.

How to change the default command line text editor in Ubuntu….

datePosted on 12:10, September 28th, 2009 by Many Ayromlou

I love Ubuntu, but there is one thing that really bugs the hell out of me. The default configured editor in Ubuntu is nano, a Pico clone. I hate Pico, therefor I hate nano :-). So how would you go about fixing this and changing the default editor to vi (or vim):

  1. Issue the following command: sudo update-alternatives --config editor
  2. Enter the superuser password when prompted.
  3. At the following screen choose the number beside the editor you want as default or alternatively just press Enter to keep the default the same.
    There are 3 alternatives which provide `editor'.

    Selection Alternative
    1 /usr/bin/vim.tiny
    2 /bin/ed
    *+ 3 /bin/nano

    Press enter to keep the default[*], or type selection number: 1
    Using '/usr/bin/vim.tiny' to provide 'editor'.

That’s it…..Have fun.

OSX 10.5: How to create a public share folder…..

datePosted on 12:39, June 11th, 2009 by Many Ayromlou

This problem has been around (I think) ever since the introduction of POSIX permissions. In pre-10.5 versions you could sorta do something like this by changing the default umask on the system, but that was system wide and applied to all folders/files a user created on the entire filesystem…..not nice. The real question is how do you create a directory that is totally public without mucking around with system/user wide settings. A folder that anyone on the system in question can read/write/modify/delete anything anyone else has put in there. A true shared directory with share permission inheritence. We call it “pub” directory at my place of work.

The old trick in OSX (in case someone is interested) was to write a small script that you ran via cron every 5-10 minutes that would “chmod” all the entries in a folder to be open to a specific POSIX group….something like the script below:

find /path/to/shared/directory ! -type l ! -perm -g=w -print0 | while IFS
= read -rd $'\0' filename
echo "*+*+*Permission changing program caught something"
if [ -d "$filename" ]then
chmod g+rwx "$filename"
# echo Directory changed
stat -l "$filename"
if [ -f "$filename" ]then
chmod g+rw "$filename"
# echo File changed
stat -l "$filename"

Well those were the old days and now with the help of ACL’s we can do this a lot nicer/cleaner. The procedure below is for OSX 10.5+ (it should also work on 10.4, although I haven’t tried it).

  1. Enable ACL’s on your computer. Type the following command in a Terminal window: sudo /usr/sbin/fsaclctl -p / -e and verify that ACL’s are now enabled by typing: sudo fsaclctl -p /
  2. Create a new group. The easiest way to do this is through the Accounts pane in System Preferences. Just click on the Plus sign to add a new account and then select Group from the New Account drop-down menu. Call this group anything you want; I called mine public. Add all the users who you want to participate in the file sharing to your newly-created group.
  3. Do the following steps in Terminal, in Applications -> Utilities:
  4. Change directory to /Users/Shared: cd /Users/Shared
  5. Create a new folder where the users will be able to share their files. I created a folder named Pub by typing mkdir Pub
  6. Change the group of the new folder to your newly-created group: sudo chown admin:public Pub
  7. Change the default permissions, if you wish: sudo chmod 770 Pub (this is optional if you’re happy with the default permissions).
  8. Create the ACL entry for the new folder:sudo chmod +a "group:public allow file_inherit,directory_inherit,readattr,readextattr,readsecurity,read,execute,list,search,writeattr,writeextattr,delete,append,write,delete_child,add_file,add_subdirectory" Pub

You now have a true public folder where all members of the group public can read, write and delete files, as well as read, write to and create new sub folders. The ACL rule takes precedence over standard UNIX file permissions and is automatically inherited. It’s this automatic inheritance that is really important.

IMPORTANT: You must copy (hold down Option in Finder prior to dragging), and not merely move, items. This is particularly important with bundles, such as the Aperture library bundle for example. Moving items doesn’t inherit/change the permissions/ACL’s. Copying ensures that the files are actually created in the shared folder, thereby forcing the ACL rules to be inherited. If you have moved files into this directory and the permissions are a bit messed up you can quickly fix that by issuing the following recursive command which will set the ACL’s and POSIX permissions to the “right” ones so that everyone can do anything in that directory:
sudo chmod -R +a "group:public allow file_inherit,directory_inherit,readattr,readextattr,readsecurity,read,execute,list,search,writeattr,writeextattr,delete,append,write,delete_child,add_file,add_subdirectory" /Users/Shared/Pub

This used to be a pain in the butt. Lots of manual apt-get lines and config edits to get it to work. Weŕe talking about installing the LAMP stack onto a preexisting Ubuntu Desktop Edition installation. I used to do this backwards in the old days by installing the Server edition first (with LAMP) and then getting the graphical desktop goodies installed on top of that. That method still works, but I found out that LAMP stack install on a Desktop edition is a simple one command affair. As of the 7.04 release, the Ubuntu base system includes Tasksel. You can install LAMP using tasksel.
sudo tasksel install lamp-server