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Remove last line from files recursively
Used this command recently to remove the trailing ?> from all the files in a php project, which has having some unnecessary whitespace issues. Obviously, change *.php to whatever you'd like.

Beep siren
Infinitely plays beeps with sinusoidally changing sound frequency. Ideal for alarm on an event.

Cut out a piece of film from a file. Choose an arbitrary length and starting time.
With: -vcodec, you choose what video codec the new file should be encoded with. Run ffmpeg -formats E to list all available video and audio encoders and file formats. copy, you choose the video encoder that just copies the file. -acodec, you choose what audio codec the new file should be encoded with. copy, you choose the audio encoder that just copies the file. -i originalfile, you provide the filename of the original file to ffmpeg -ss 00:01:30, you choose the starting time on the original file in this case 1 min and 30 seconds into the film -t 0:0:20, you choose the length of the new film newfile, you choose the name of the file created. Here is more information of how to use ffmpeg: http://www.ffmpeg.org/ffmpeg-doc.html

Find the package that installed a command

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Delete all aliases for a network interface on a (Free)BSD system
The example command deletes all aliases for network interface 'em0' assuming that the aliases have netmask of 255.255.255.255 and the master IP has some other netmask (such as 255.255.255.0). See here -> http://my.galagzee.com/2009/07/22/deleting-all-network-interface-aliases/ for more on the rationale of this command.

Prettify XML in pipeline
xmllint2 comes with GNU libxml2 library. (based on: http://vim.wikia.com/wiki/Format_your_xml_document_using_xmllint)

Preview of a picture in a terminal
This command allows you to see a preview of a picture via the terminal. It can be usefull when you are ssh'ing your server without X-forwarding. To have en example of the output you can get with this command see http://www.vimeo.com/3721117 Download at http://inouire.net/image-couleur.html Sources here: http://inouire.net/archives/image-couleur_source.tar.gz

a function to find the fastest DNS server
http://public-dns.info gives a list of online dns servers. you need to change the country in url (br in this url) with your country code. this command need some time to ping all IP in list.


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