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check the status of 'dd' in progress (OS X)
While a dd is running in one terminal, open another and enter the while loop. The sample output will be displayed in the window running the dd and the while loop will exit when the dd is complete. It's possible that a "sudo" will need to be inserted before "pkill", depending on your setup, for example: $ while pgrep ^dd; do sudo pkill -INFO dd; sleep 10; done

tar pipe to copy files, alternate to cp -Ra
uses tar to dump files from /orignl/path to /dst/dir. i find tar's out more readable than cp, and it doesn't mess with modified dates.

check open ports without netstat or lsof

Sorts and compare 2 files line by line

Password generator
https://xkcd.com/936/ introduced us to what actually is a good password. Here's such an implementation. Credit: quinq on #suckless

resize all JPG images in folder and create new images (w/o overwriting)
Convert all jpegs in the current directory into ~1024*768 pixels and ~ 150 KBytes jpegs

Create a Multi-Part Archive Without Proprietary Junkware
Leave it to a proprietary software vendor to turn a cheap and easy parlor trick into a selling point. "Hey guys, why don't we turn our _collection of multiple files_ into a *collection of multiple files*!!" Extract the ^above with this: $ cat pics.tar.gz.??? | tar xzv ^extract on any Unix - no need to install junkware! (If you must make proprietary software, at least make it do something *new*) if [ -e windows ]; then use 7-Zip

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Redirect incoming traffic to SSH, from a port of your choosing
Stuck behind a restrictive firewall at work, but really jonesing to putty home to your linux box for some colossal cave? Goodness knows I was...but the firewall at work blocked all outbound connections except for ports 80 and 443. (Those were wide open for outbound connections.) So now I putty over port 443 and have my linux box redirect it to port 22 (the SSH port) before it routes it internally. So, my specific command would be: $iptables -t nat -A PREROUTING -p tcp --dport 443 -j REDIRECT --to-ports 22 Note that I use -A to append this command to the end of the chain. You could replace that with -I to insert it at the beginning (or at a specific rulenum). My linux box is running slackware, with a kernel from circa 2001. Hopefully the mechanics of iptables haven't changed since then. The command is untested under any other distros or less outdated kernels. Of course, the command should be easy enough to adapt to whatever service on your linux box you're trying to reach by changing the numbers (and possibly changing tcp to udp, or whatever). Between putty and psftp, however, I'm good to go for hours of time-killing.


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