UpFront

The UpFront Section

UpFront

Tech Tip

If you try to unmount a partition and get a message like this:

# umount /media/usbdisk/
umount: /media/usbdisk: device is busy

use the lsof command to find out what programs are using what files:

# lsof /media/usbdisk/
COMMAND  PID USER  FD TYPE DEVICE SIZE NODE NAME
bash    6925 root cwd  DIR   8,17 4096    1 /media/usbdisk/
xmms    6979 root cwd  DIR   8,17 4096    1 /media/usbdisk/

This shows that the programs bash and xmms are using the device. For an even clearer picture, use the device name rather than the mountpoint:

# lsof /dev/sdb1
COMMAND  PID USER  FD TYPE DEVICE    SIZE NODE NAME
bash    6925 root cwd  DIR   8,17    4096    1 /media/usbdisk
xmms    6979 root cwd  DIR   8,17    4096    1 /media/usbdisk
xmms    6979 root  8r  REG   8,17 2713101  377 /media/usbdisk/a.mp3

You either can wait until those processes exit or terminate them manually.

Tech Tip

To search a list of RPM files for a particular file, execute the following command:

$ ls RPMS-TO-SEARCH | \
    xargs rpm --query --filesbypkg --package | \
      grep FILE-TO-SEARCH-FOR

Replace RPMS-TO-SEARCH with the names of the RPM files to search, and replace FILE-TO-SEARCH-FOR with the name of the file to search for. The --filesbypkg option tells the rpm command to output the name of the package as well as the name of the file.

Tech Tip

If you need to transfer an entire filesystem from one machine to another, for example, when you get a new computer, do the following steps.

1) Boot both PCs with any Linux live CD (for example, Knoppix), and make sure they can access each other via the network.

2) On the source machine, mount the partition containing the filesystem to be copied, and start the transfer using netcat and tar:

cd /mnt/sda1
tar -czpsf - . | pv -b | nc -l 3333

3) On the destination machine, mount the partition to receive the filesystem, and start the process:

cd /mnt/sda1
nc 192.168.10.101 3333 | pv -b | tar -xzpsf -

The nc (netcat) command is used for any kind of TCP connections between two hosts. The pv (progress viewer) command is used to display the progress of the transfer. tar is used to archive the files on the source machine and un-archive them on the destination.

______________________

Webinar
One Click, Universal Protection: Implementing Centralized Security Policies on Linux Systems

As Linux continues to play an ever increasing role in corporate data centers and institutions, ensuring the integrity and protection of these systems must be a priority. With 60% of the world's websites and an increasing share of organization's mission-critical workloads running on Linux, failing to stop malware and other advanced threats on Linux can increasingly impact an organization's reputation and bottom line.

Learn More

Sponsored by Bit9

Webinar
Linux Backup and Recovery Webinar

Most companies incorporate backup procedures for critical data, which can be restored quickly if a loss occurs. However, fewer companies are prepared for catastrophic system failures, in which they lose all data, the entire operating system, applications, settings, patches and more, reducing their system(s) to “bare metal.” After all, before data can be restored to a system, there must be a system to restore it to.

In this one hour webinar, learn how to enhance your existing backup strategies for better disaster recovery preparedness using Storix System Backup Administrator (SBAdmin), a highly flexible bare-metal recovery solution for UNIX and Linux systems.

Learn More

Sponsored by Storix