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Check a directory of PNG files for errors
Useful for checking if a large number of PNG files was downloaded successfully by verifying the built-in CRC checksum. For incomplete files, the command will print: "00002309.png EOF while reading IDAT data ERROR: 00002309.png" The process is very fast; checking 21,000 files of 5MB in size took only five minutes on a 2011 Intel mobile dual-core.

Video thumbnail
Faster thumbnail creation than '-itsoffset' $ffmpeg -itsoffset -4 -i test.avi -vcodec mjpeg -vframes 1 -an -f rawvideo -s 320x240 test.jpg

find and reduce 8x parallel the size of JPG images without loosing quality via jpegoptim

Rename files in batch

Show IP Address in prompt --> PS1 var
when working with many machines in a computer lab need to know the IP addr is very large, this is a simplistic solution to make things easier

remove ^M characters from file using sed
removing ^M characters from file with sed

Top 10 Memory Processes
It displays the top 10 processes sorted by memory usage

Batch convert PNG to JPEG
Convert all PNG images in directory to JPEG using ImageMagick, and delete the old PNG images.

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

tcmdump check ping
capture only ping echo requests with tcpdump


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