Easily take a screen shot with the powerful ImageMagick image manipulation program that comes preinstalled on most Linux operating systems. If perhaps your Linux OS does not have ImageMagick preinstalled, you can easily install it from your distro's package manager - ImageMagick is certain to be readily available in your distro's repository.

Howto:

1). Open a terminal

2). Type this command:

import -geometry 400x400 ~/Desktop/myimage.png

3). Press enter

4). A cross will appear on mouse pointer. Hold the left mouse button compressed at the top left or right corner of your screen capture image and drag the rectangular wire frame box over the image, letting go of the compressed left mouse button when you have completed including your entire image. ImageMagick will automatically take the screen shot, placing it in your ~/Desktop folder.

In the command above "import" is the ImageMagick call command and "-geometry" is the option to allowing image size to be set. "400x400" is the image size you can change this to any size you desire. "~/Desktop" is the relative location of your Desktop folder and /myimage.png is the image name and type extension. You can choose from any common extension such as jpg; jpeg; gif; png; bmp; etc. Numerous other CLI options are available for the ImageMagick application screen shot tool. Get the full list of options through this link: OPTIONS

Extension type handling on your system can be found by typing this command in your Linux terminal: [identify -list format]

NOTE: About image SIZE option. ImageMagick can perform two steps at one time when you select your image with the rectangular wire frame. Your actual selection may be any size, but ImageMagick will save your image at the SIZE OPTION that you set in your command. There is no need then to resize the image after the screen shot is taken because you set your desired SIZE in the command that you enter.

1). Getting audio/video file information

ffmpeg -i video.mp4

2). Converting video files to different formats. See ffmpeg guide

NOTE: To check what formats your system can process first run:

ffmpeg -formats

ffmpeg -i video.flv video.mpeg

3). Converting video files to audio files

ffmpeg -i input.mp4 -vn -ab 320 output.mp3

4). Extracting audio from a video. See ffmpeg guide

ffmpeg -i input.mkv -acodec libmp3lame output.mp3

5). Increase audio volume in video or audio media. See ffmpeg guide

ffmpeg -i inputfile -vcodec copy -af "volume=10dB" outputfile

ffmpeg -i input.mkv -filter:a "volume=10dB" output.mkv

6). Record desktop audio and video using alsa or pulse. See ffmpeg site

NOTE: If you wish replace pulse with alsa and when using alsa you may need to specify which hardware device. alsa -i "hw:0" to replace "default"

ffmpeg -f pulse -ac 2 -i default -f x11grab -r 30 -s 1920x1080 -i :0.0 -acodec pcm_s16le -vcodec libx264 -preset ultrafast -threads 0 -y output.mkv

ffmpeg -f x11grab -video_size 1360x768 -framerate 30 -i :0.0 -f pulse -i default -preset ultrafast -crf 18 -pix_fmt yuv420p out.mkv

7). Record from webcam

ffmpeg -f alsa -ac 2 -i default -itsoffset 00:00:00.5 -f video4linux2 -s 320x240 -r 25 -i /dev/video0 out.mpg

8). Record sound only

ffmpeg -f pulse -i default output.wav

You can use other audio extensions if you desire to compress the audio quality.