Tag Archives: linux

Unzip all files in a folder (Linux)

Have you ever had the problem that you needed to extract all zip-files in a folder and found that ‘unzip *.zip’ doesn’t work?

The solution is to escape the *. You need to use ‘unzip \*.zip’.

Create and extract comptessed tar archieves

Because i google this so often:

 

To add a complete directory to a tar file and compress the tar use this:
tar cfvz NAME.tar.gz [DIRECTORY]

To extract the files use:
tar xfvz NAME.tar.gz

 

If you have many files in the directory it might be a good idea to leave the v parameter out.

Add additional loop device on Linux

  • mknod created a new device.
  • -m660 sets the mode to 660 for the filesystem.
  • /dev/loop8 specifies the device to create.
  • b sets the device as a block device.
  • 7 and 8 are major and minor device numbers.

So this creates on a standard Linux the eighth loopback device.

mknod -m660 /dev/loop8 b 7 8
chown root.disk /dev/loop8
chmod 666 /dev/loop8

Mount an encrypted file as loopback device (linux)

  1. Make sure you have the required modules in the kernel. Use ‘modprobe cryptoloop’ and ‘modprobe aes’.
  2. Create empty 100MB file imageĀ  named MyImage.img with ‘dd if=/dev/urandom of=MyImage.img bs=1M count=100’. Be warned, this my take some minutes.
  3. ‘losetup -e aes /dev/loop0 MyImage.img’ connects your image to loop0.
  4. You have to enter your new password now.
  5. With ‘mkfs -t ext2 /dev/loop0’ formats your new ‘drive’.
  6. ‘mount /dev/loop0’ and
  7. ‘mount -o loop,encryption=aes MyImage.img /mysafe’ mount your new document safe to /mysafe. You might need to create /mysafe before that.

Install samba on debian and connect with windows 7

  1. Install samba with ‘apt-get install samba’
  2. Follow the install wizard and enter ‘workgroup’ and if you use a dhcp server
  3. Add a directory for samba shares. ‘mkdir /samba
  4. Add a usergroup for samba. ‘groupadd sambauser’
  5. Give directory to the group. ‘chgrp sambauser /samba’
  6. Change the rights. ‘chmod 770 /samba’
  7. Add a user. ‘useradd -g sambauser windowsclient’
  8. Give the user a password. ‘passwd windowsclient
  9. Add samba password, make it the same as the linux user password. ‘smbpasswd -a windowslcient’
  10. Enable user in samba. ‘smbpasswd -e windowsclient’
  11. Add the following to /etc/samba/smb.conf

      [MyShare]
      path = /samba
      writable = yes
      public = no
      valid users = windowsclient
      force create mode = 0770
      force directory mode = 0770
  12. Restart samba with /etc/init./samba restart’.

Now you should see your server under network on the windows system and can connect using the account windowsclient / password.

Debian 5.0 (lenny) on NSLU2

I had this old Cisco NSLU2 around, doing nothing other than bringing an even older USB HDD to the network. And i honestly never really used it, because the truth is, the NSLU2 is slow.

So i found this great site where they explain how to flash Linux on the device some time ago. And now, after having to set up a few Debian server and no reasonable way to hide from it, i decided to put a Debian on the NSLU2.

The instructions are quite simple as the device is supported by Debian 5.0.

Some advice from personal experience:

  • Use a singe 2,5” (notebook) USB drive. With 2 drives, powered over USB, you might get problems with the power supply. One works great for me.
  • Expect to spend up to 3 hours on this. Without playing, just installing and configuration.
  • Do not expect the NSLU2 to perform like a computer or vps. It is slow, but its performance positively surprised me.
  • Use the provided unofficial image.

Wget quick howto: Examples for the most common uses

If you are using linux on your computer or operate your own (virtual-)server you will likely be faced with the problem to transfer data from an other computer/server to your own.

wget is a little linux tool that i usually in a standard installation. Here are a few examples for the most common uses. If you need a more in-depth explanation, please consult the man pages.

Getting a single file from remote location:

Specify the number of downloads attempts:

Continue a interrupted download:

Login credentials needed? No problem:

Download a webpage or something else recursive:

Want to download all pictures from a list of websites?

  • -A jpg,gif,png,bmp,jpeg specifies a acceptlist of file extensions.
  • -i filename to specify a file with the websites
  • -q suppresses messages to the console
  • wget -i mylist.txt -A jpg,gif,png,bmp,jpeg -q -r -l 10
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