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Old 12-09-2006, 05:21 PM   #1
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Odds and ends

I can't keep track of it all. So what I do is establish a file on my Home directory called Jims_HowTos. This file contains tips and things I have learned (usually the hard way), that I'll never remember unless I write them down.

Just for grins, here's a few of my odds and ends of things I've learned along the way.:

Two-pass rip of a .VOB file to a divx (mpg4) file using transcode:
transcode -a 0 -b 128,0,0 -i movie.vob -w 1800,250,100 -A -N 0x2000 -M 2 -Y 4,4,4,4 -B 1,11,8 -R 1 -x vob -y xvid4,null
transcode -a 0 -b 128,0,0 -i movie.vob -w 1800,250,100 -A -N 0x2000 -M 2 -Y 4,4,4,4 -B 1,11,8 -R 2 -x vob -y xvid4 -o movie.avi
One thing to note is that for DVDs, this will output the FPS to 29.97. If you want to do 23.97 (and you *know* the DVD is that framerate) then add "-f 24,1" to the mix of flags.

If your framerate is wrong, you'll notice pretty easily -- the video will skip a little bit though the audio will be fine.

One easy way to determine for sure what the FPS of the source video, is to actually play it with MPlayer where you can see the output.

To monitor system and file calls of a program, start it with strace myprog.


To create a block device for the zip drive when it doesn't get picked up by the system on startup:

go to /dev/ide. Create directory structure bus1/target0/lun0

Then use command mknod disc b 22 0

Note that major number can be obtained from /proc/devices and minor number simply means first device. Should also mknod part4 b 22 4 to pick up the partition on the zip disk.

Note change in mandriva 2007:

create device /dev/hdc as mknod hdc b 22 0
then create device /dev/hdc4 as mknod hdc4 b 22 4
then go into /dev/disk/by-path and create these links:
ln -s ../../hdc pci-0000:00:22.0-ide-1:0
ln -s ../../hdc4 pci-0000:00:22.0-ide-1:0-part4

I created a simple script to do this in init.d called mountzip

Then mount the zip disk


Perl regex tutorial: man perlretut


When changing nic that accesses internet in Linux, need to change samba, all the standard net connect stuff, and DON'T FORGET THE FIREWALL!!! (we are using endoshield)


Kmail loses track of a mailbox. This usually means the index for that box is corrupt. The solution is to delete the index file(s) which are found in ~/.Mail then restart Kmail. This will cause it to recreate the index. This might happen if the HD runs out of space.


Problems with the system (./configure) finding the right gtk+-
I don't know what is happening here. But the solution is to enter this command:

export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig
I should put that into the startup scripts.


mounting a hd iso as a cdrom

establish mountpoint in /mnt or other place
mount -o loop -t iso9660 myiso.iso /mnt/isoimage/


Sizing partitions, determining start and end using linux fdisk, and organizing so dd can image

fdisk -l will give an output that specifies the # heads, the # of sectors/track, and the number of cylinders on the drive. For each partition, fdisk will list the starting cylinder and the ending cylinder, and the size in sectors; by default the formatting tools will use cylinder boundaries. Linux uses sectors that are 1024 bytes, which is 2 - 512 byte blocks. dd wants the starting sector and the size of the partition, in appropriate units. Default size for dd is blocks of 512 bytes.

To get the starting sector of the partition, take the end cylinder of the previous partition. Multiply that number by the number of sectors/track, then by the number of heads. This gives the first sector of the last track of the previous partition. Now add in the number of sectors/track to this number and the result is the first sector of the first track of the first cylinder of the next partition.

To get the size of the partition, subtract the beginning cylinder from the end cylinder and add one (to get the cylinder count). Then multiply this number by the sectors/track and the # heads. Then subtract the sectors/track from the result to get the total sectors in the partition. The size of the partition may also be determined in sectors by taking the size listed by fdisk (in "blocks"), multiplying it by 2, and adding 1.

Alternatively, sfdisk -l -sf /dev/sd# will give the start block and size directly
Old 12-29-2006, 03:59 AM   #2
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my favorite:

rm -rf *

(read mail, really fast, and all of it)
Old 01-28-2007, 09:08 AM   #3
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Originally Posted by dombrowsky
my favorite:

rm -rf *

(read mail, really fast, and all of it)
And for the benefit of any complete newbies who are reading this, if you really execute this command (as root) it will have the effect of deleting the entire hard drive
Old 01-28-2007, 09:47 AM   #4
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More in the Tips and tricks thread...


howto, notes, random, reference

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