Commands by kenbarbour (1)

What's this? is the place to record those command-line gems that you return to again and again. 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.

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

Ping all hosts on

Find the 20 biggest directories on the current filesystem
This command will tell you the 20 biggest directories starting from your working directory and skips directories on other filesystems. Useful for resolving disk space issues.

Recursively find top 20 largest files (> 1MB) sort human readable format
from my bashrc ;)

Decode base64-encoded file in one line of Perl
Another option is openssl.

Determine if photos have been rotated to portrait orientation instead of normal landscape orientation
Most people take photos in landscape orientation (wider than it is tall). Sometimes though you turn the camera sideways to capture a narrow/tall subject. Assuming you then manually rotate those picture files 90 degrees for proper viewing on screen or photo frame, you now have a mix of orientations in your photos directory. This command will print out the names of all the photos in the current directory whose vertical resolution is larger than its horizontal resolution (i.e. portrait orientation). You can then take that list of files and deal with them however you need to, like re-rotating back to landscape for consistent printing with all the others. This command requires the "identify" command from the ImageMagick command-line image manipulation suite. Sample output from identify: $ identify PICT2821.JPG PICT2821.JPG JPEG 1536x2048 1536x2048+0+0 8-bit DirectClass 688KB 0.016u 0:00.006

Find usb device in realtime
Using this command you can track a moment when usb device was attached.

Recover tmp flash videos (deleted immediately by the browser plugin)
Newer versions of the flashplayer browser plugin delete the tmp flash video immediately after opening a filehandle to prevent the user from "exporting" the video by simply copying the /tmp/FlashXYZ file. This command searches such deleted flash videos and creates symbolic links to the opened filehandle with the same name as the deleted file. This allows you to play your flash-videos (from e.g. youtube) with e.g. mplayer or copy the buffered video if you want to keep it.

Count number of files in a directory

Trick find -exec option to execute alias
An alias cannot be executed as command in a find -exec line. This form will trick the command line and let you do the job.

Stay in the loop…

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