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Which Twitter user are you?
This will tell you which twitter user you are chronologically. For example, a number of 500 means you were the 500th user to create a twitter account.

a shell function to print a ruler the width of the terminal window.
A similar version for Bash that doesn't require cut and shortens the function in a few places. And it uses local variables. (similar to a version by eightmillion in a comment on the another version)

check open ports without netstat or lsof

Hide or show Desktop Icons on MacOS
Hides all Files and Folders on the MacOS Desktop. To show files and folders, type "true" instead of "false". "Finder" at the end is case sensitive, "finder" doesn’t work

Find running binary executables that were not installed using dpkg
This helped me find a botnet that had made into my system. Of course, this is not a foolproof or guarantied way to find all of them or even most of them. But it helped me find it.

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"

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Synchronize date and time with a server over ssh
If you are stuck behind a firewall and want to synchronize time with another server but you do not want to port forward NTP (which uses UDP) then this command is handy. It gets the time from a server and sets the local time. It is not that accurate but I can live with a second or so drift.

blktrace - generate traces of the i/o traffic on block devices
blktrace is a block layer IO tracing mechanism which provide detailed information about request queue operations up to user space. blkparse will combine streams of events for various devices on various CPUs, and produce a formatted output the the event information. It take the output of above tool blktrace and convert those information into fency readable form.

Do some Perl learning...
Prerequisites: module Pod::Webserver installed. You can install it typing: $ sudo perl -MCPAN -e 'install Pod::Webserver' You can replace elinks with your fav browser. For FF: $podwebserver& sleep 2; firefox -remote 'openurl( http://127.0.0.1:8020/, new-tab )' If you have Firefox open, this will pop-up the index web in a new tab.


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