Here is a breakdown of modern python development tools https://pycon.switowski.com/02-packages/pipx/
Saturday, May 15, 2021
This usually happens when the nfs server is down, you cannot umount
the nfs mount, because the system will say "not found or server not
$ sudo umount /opt/logs/production umount.nfs: nfs.local:/var/lib/backup: not found / mounted or server not reachable umount.nfs: nfs.local:/var/lib/backup: not found / mounted or server not reachable
To fix this, you need to force mount it with lazy flag:
$ sudo umount -f -l /opt/logs/productionwhere -f is to do force unmount, and -l is for lazy unmounting. From man:
"Lazy unmount. Detach the filesystem from the filesystem hierarchy now, and cleanup all references to the filesystem as soon as it is not busy anymore."
Post borrowed from: https://www.linuxwave.info/2013/06/unmounting-stuck-nfs-mounts.html
Thursday, May 6, 2021
I learned recently about the fzf linux cli command. This is a text finder similar to grep but a lot more powerful. It can be used not only to find text but files as well in an interaftive mode.
It exists as a package for debian and its github page is: https://github.com/junegunn/fzf
Saturday, April 24, 2021
First convert the subtitles to .ass format: ```` ffmpeg -i sub.srt sub.ass ```` Then add them using a video filter: ```` ffmpeg -i in.mp4 -vf ass=sub.ass out.mp4 ```` ## Extract the frames from a video To extract all frames from between 1 and 5 seconds, and also between 11 and 15 seconds: ```` ffmpeg -i in.mp4 -vf select='between(t,1,5)+between(t,11,15)' -vsync 0 out%d.png ```` To extract one frame per second only: ```` ffmpeg -i in.mp4 -fps=1 -vsync 0 out%d.png ```` ## Rotate a video Rotate 90 clockwise: ```` ffmpeg -i in.mov -vf "transpose=1" out.mov ```` For the transpose parameter you can pass: ```` 0 = 90CounterCLockwise and Vertical Flip (default) 1 = 90Clockwise 2 = 90CounterClockwise 3 = 90Clockwise and Vertical Flip ```` Use `-vf "transpose=2,transpose=2"` for 180 degrees. ## Download "Transport Stream" video streams 1. Locate the playlist file, e.g. using Chrome > F12 > Network > Filter: m3u8 2. Download and concatenate the video fragments: ```` ffmpeg -i "path_to_playlist.m3u8" -c copy -bsf:a aac_adtstoasc out.mp4 ```` If you get a "Protocol 'https not on whitelist 'file,crypto'!" error, add the `protocol_whitelist` option: ```` ffmpeg -protocol_whitelist "file,http,https,tcp,tls" -i "path_to_playlist.m3u8" -c copy -bsf:a aac_adtstoasc out.mp4 ```` ## Mute some of the audio To replace the first 90 seconds of audio with silence: ```` ffmpeg -i in.mp4 -vcodec copy -af "volume=enable='lte(t,90)':volume=0" out.mp4 ```` To replace all audio between 1'20" and 1'30" with silence: ```` ffmpeg -i in.mp4 -vcodec copy -af "volume=enable='between(t,80,90)':volume=0" out.mp4 ```` ## Deinterlace Deinterlacing using "yet another deinterlacing filter". ```` ffmpeg -i in.mp4 -vf yadif out.mp4 ```` ## Create a video slideshow from images Parameters: `-r` marks the image framerate (inverse time of each image); `-vf fps=25` marks the true framerate of the output. ```` ffmpeg -r 1/5 -i img%03d.png -c:v libx264 -vf fps=25 -pix_fmt yuv420p out.mp4 ```` ## Extract images from a video - Extract all frames: `ffmpeg -i input.mp4 thumb%04d.jpg -hide_banner` - Extract a frame each second: `ffmpeg -i input.mp4 -vf fps=1 thumb%04d.jpg -hide_banner` - Extract only one frame: `ffmpeg -i input.mp4 -ss 00:00:10.000 -vframes 1 thumb.jpg` ## Metadata: Change the title ```` ffmpeg -i in.mp4 -map_metadata -1 -metadata title="My Title" -c:v copy -c:a copy out.mp4