Commands by aix (1)

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Recursive grep of all c++ source under the current directory

Piping Microphone Audio Over Netcat
Send microphone audio to another computer using netcat and arecord. Connect to the stream using "nc [other ip] 3333|aplay" You can set up two-way communication by piping audio the reverse direction on another port: Machine #1: $arecord -D hw:0,0 -f S16_LE -c2|nc -l 3333 &;nc -l 3334|aplay Machine #2: $$ip=[machine1_ip];arecord -D hw:0,0 -f S16_LE -c2|nc $ip 3334 &;nc $ip 3333|aplay

Find usb device in realtime
Using this command you can track a moment when usb device was attached.

Convert a bunch of HTML files from ISO-8859-1 to UTF-8 file encoding in a folder and all sub-folders
This is my first attempt at converting all HTML files to UTF-8 file encoding, including all subfolders. Theres probably a much more compact way to do it, but I'm quite proud of it with my windows background ;)

What is the use of this switch ?
e.g. $ manswitch grep -o This will take you to the relevant part of the man page, so you can see the description of the switch underneath.

Bash scripts encryption and passphrase-protection
This function will encrypt a bash script and will only execute it after providing the passphrase. Requires mcrypt to be installed on the system. $ cat hello #!/bin/bash case "$1" in ""|-h) echo "This is the fantastic Hello World. Try this:" $(basename $0) "[entity]" ;; moon) echo Good night. ;; sun) echo Good morning. ;; world) echo "Hello, world!" ;; *) echo Hi, $@. ;; esac $ scrypt hello Enter the passphrase (maximum of 512 characters) Please use a combination of upper and lower case letters and numbers. Enter passphrase: Enter passphrase: Stdin was encrypted. $ cat hello.scrypt . <(echo "$(/usr/bin/tail -n+2 $0|base64 -d|mcrypt -dq)");exit; AG0DQHJpam5kYWVsLTEyOAAgAGNiYwBtY3J5cHQtc2hhMQAV34412aaE8sRzQPQzi09YaNQPedBz aGExAARvB6A/HYValW4txoCFmrlp57lmvhKBbM4p+OUiZcCxr6Y+Mm7ogg3Y14pHi0CrfT70Tubq 9g8/kNJrQr7W/ogHpVuOOdD0YfuRatrV7W2+OlNQ63KX780g4qTHrTqNnyLp8sF5RQ7GwxyZ0Oti kROtVIU4g4+QAtn/k/e7h7yt4404VF1zzCYRSw20wmJz1o/Z0XO7E/DFBr5Bau7bWjnF7CRVtims HGrDwv1miTtAcyB9PknymDxhSyjDUdNhqXGBIioUgqjX1CKgedtO0hQp050MiQd3I6HacpSrVUIW kuuS+BtMrxHDy+48Mh1hidV5JQFP7LP5k+yAVLpeHd2m2eIT1rjVE/Bp2cQVkpODzXcWQDUAswUd vulvj/kWDQ== $ ./hello This is the fantastic Hello World. Try this: hello [entity] $ ./hello.scrypt Enter passphrase: This is the fantastic Hello World. Try this: hello.scrypt [entity] $ ./hello world Hello, world! $ ./hello.scrypt world Enter passphrase: Hello, world!

Create the signature base string required for a Twitter stream feed
This is the SECOND command in a set for five that are needed for a Twitter stream feed. This command creates variable "b", the so-called "base string" required for oauth in Twitter stream feed requests. (The 256 char limit prevents giving it a better name) We use five environment variables created by a previous step: id, k1, once, ts and k3. The five environment variables are created in a separate command, please see my other commands. For more information on the signature base string, see dev.twitter.com/apps, click on any app (or create a new one) and then go to the "OAuth Tool" tab.

Map the slot of an I/O card to its PCI bus address
Recent hardware may or may not enumerate *both of* these values

DVD ripping with ffmpeg
To rip DVD movie to ogg format using ffmpeg, follow these steps. 1) find the vob files on the mounted video DVD in VIDEO_TS that stores the movie itself. There would be a few other VOB files that stores splash screen or special features, the vob files for the movie itself can be identified by its superior size. You can verify these vob files by playing them directly with a player (e.g. mplayer) 2) concatenate all such vob files, pipe to ffmpeg 3) calculate the video size and crop size. The ogg video size must be multiple of 16 on both width and height, this is inherit limitation of theora codec. In my case I took 512x384. The -vcodec parameter is necessary because ffmpeg doesn't support theora by itself. -acodec is necessary otherwise ffmpeg uses flac by default.

Delete files older than..
This command will delete files i a given path (/dir_name) , which older than given time in days (-mtime +5 will delete files older than five days.


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