The 30 means start extracting frames from 30 seconds into the video. The 3 means extract the next 3 seconds from that point. The fps can be adjusted based on your preferences. The 320 is the width of the gif, the height will be calculated automatically. input.mp4 is the video file, which can be any video file ffmpeg supports. The output.gif is the gif created.

This begins recursively looking at dot files starting from "./path_to_dir". Then it prints out the names of those files. If you are satisfied with the list of files discovered then you can delete them like so `find ./path_to_dir -type f -name '.*' -exec rm '{}' \;` which executes the removal program against each of those names previously printed. This is useful when you want to remove thumbnail files on Mac OSX/Windows or simply want to reset an app's configuration on Linux.

Create a 7zip archive named "some_directory.7z" and adds to it the directory "some_directory". The `-mhe=on` is for header encryption, basically it mangles the file names so no one knows whats inside the 7z. If -mhe=on wasn't included, then a person without the password would still be able to view the file names inside the 7z. Having this option ensures confidentiality. To ensure the result is small use lzma2, level 9 compression. Lzma2 fast bytes range from 5 to 272, the higher the number the more aggressive it is at finding repetitive bytes that can be added to the dictionary. Here the fast bytes are set to 64 bytes and the dictionary is 32 MB. Depending on your purposes (the directory size and desired file size), you can be more aggressive with these values. Lastly, `-ms=on` just says concatenate all the individual files and treat them as a singular file when compressing. This leads to a higher compression ratio generally.

Extracts the binary from the .text section and escapes it. This puts it in a form ready to use in a program. Show Sample Output

When you want to know the duration of all your mp3 files in the current working directory this command will tell you based on exif data. Since it relies on exif data it can be used against other files like movies, ogg vorbis etc. also. Useful when you want to know how long it will take to listen to an album or series of lectures. Show Sample Output