FFmpeg can be considered the Swissknife of audio and video applications, with many options and possibilities. You probably already have it installed on your computer as a dependency of a program you use to watch videos or listen to music. In this article we will see some use from the command line without using graphics applications.
In these days I have seen in a somewhat more detailed way collectd, an excellent tool for collecting statistics on various aspects of our Linux servers.
From Wikipedia: “collectd is a UNIX-daemon which collects, transfers and stores performance data of computers and network equipment. The acquired data is meant to help system administrators maintain an overview over available resources in order to detect existing or looming bottlenecks.
The first version of the daemon was written in 2005 by Florian Forster and has been further developed as free open-source project. Other developers have written improvements and extensions to the software that have been incorporated into the project. Most files of the source code are licensed under the terms of the GNU General Public License, version 2 (GPLv2), the remaining files are licensed under other open source licenses”
In a former article we saw something about Inotify.
inotify is a Linux kernel subsystem that acts to extend filesystems to notice changes to the filesystem, and report those changes to applications. It replaces an earlier facility, dnotify, which had similar goals.
Last time I focused on the functionality of inotifywait command which can be used by shell to wait for a certain event and then perform other functions, but today we will see some uses of incron.
This program is an “inotify cron” system. It consists of a daemon and a table manipulator. You can use it a similar way as the regular cron. The difference is that the inotify cron handles filesystem events rather than time periods. Continue reading »
Among the commands available from the linux terminal there’s also cut, very useful for processing strings and characters in general.
The cut command is one of the oldest Unix command. That means that it is more then 40 years old. And it shows. It is important to understand that this is a Unix command and behaves in “Unix way”. For example, it uses IFS (Input Field Separators) to determine where to split fields. You can check it with set | grep IFS. You can also set it, for example, to:
IFS=" tn"
The cut command takes a vertical slice of a file, printing only the specified columns or fields. The columns are selected using the standard IFS or one specified. Continue reading »
Sometimes happen that your desktop freeze and you cannot do anything, so the only choice is to unplug the power cord ?
No, Linux has the magic SysRq key that can sync your disk and issue a reboot of your system…and many more things.
What is the magic SysRq key?
It is a ‘magical’ key combo you can hit which the kernel will respond to
regardless of whatever else it is doing, unless it is completely locked up.
Continue reading »