commandlinefu.com is the place to record those command-line gems that you return to again and again.
Delete that bloated snippets file you've been using and share your personal repository with the world. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.
You can sign-in using OpenID credentials, or register a traditional username and password.
First-time OpenID users will be automatically assigned a username which can be changed after signing in.
Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.
Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):
Subscribe to the feed for:
Wow, didn't really expect you to read this far down. The latest iteration of the site is in open beta. It's a gentle open beta-- not in prime-time just yet. It's being hosted over at UpGuard (link) and you are more than welcome to give it a shot. Couple things:
Creates a 2 second video clip from an image.
Useful for when you download movies split into < 700mb parts.
mencoder is generally included with mplayer.
sudo port install mplayer
We take the first 50 frames of a.mp4 for track a, and 24 blank frames followed by b.mp4 for track b. We then create a transition from track a to track b starting from frame 25 and ending at frame 49.
The output is stored in out.mp4
To view the results without saving remove "-consumer avformat:out.mp4" from the end.
Documentation of the mlt framework and the melt command can be found here: http://www.mltframework.org/bin/view/MLT/Documentation
Replace vid.mp4 with the path to your original video file, and out.mp4 to the path where you want to save the new file.
To view the output first before saving, remove "-consumer avformat:out.mp4" from the end.
Documentation for mlt framework and melt command can be found here:
Takes all the .3gp files in the directory, rotates them by 90 degrees, and saves them in the lossless ffv1 encoding.
If this rotates in the wrong direction, you may want transponse=1
Re-encoding to ffv1 may result in a significant increase in file size, as it is a lossless format. Other applications may not recognize ffv1 if they don't use ffmpeg code. "huffyuv" might be another option for lossless saving of your transformations.
The audio may be re-encoded as well, if the encoding used by your 3gp file doesn't work in a avi container.
The following will take frames starting at 15.2 seconds for a total of 45.9 seconds:
mencoder -ss 15.2 -endpos 30.7 -oac copy -ovc copy mymovie.avi -o myeditedmovie.avi
Keep in mind -endpos is the total time, i.e. the output video in this is 3 minutes 3 seconds in length:
mencoder -ss 1 minute -endpos 2 minutes 3 seconds -oac copy -ovc copy mymovie.avi -o myeditedmovie.avi
concatenates avi files
create a copy of a video file without the audio tracs
Good old cat & output redirection. Using this method you can combine all kinds of things - even mpeg files. My video camera makes a series of .mpeg files that are broken into 4gb chunks. Using this command I can easily join them together. Even better, combined with the cp command the files can be copied and joined in one step.
When playback of AVI files (containing a video format like XviD or DivX) is stuttering, it in 90% of the files is caused by a poorly or wrongly interleaved file. The issue can be permanently resolved by RE-MUXING the AVI video-files that have this problem
-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: