Commands by seungwon (6)

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Random Number Between 1 And 256
It takes a byte from /dev/random whose source is the kernel entropy pool (better source than other solutions).

Read a tcpdump file and count SYN packets to port 80, Order column by destination.

Clear the terminal screen
works in /bin/bash

Create Solid Archive (best compression) with 7z
Creates a solid archive with the highest possible compression (Ultra). Advantage of 7z is that it will use all the processor cores to create the archive. (Ok. at least version 9.04 does)

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" }

Remove trailing space in vi

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"

move contents of the current directory to the parent directory, then remove current directory.
Robust means of moving all files up by a directory. Will handle dot files, filenames containing spaces, and filenames with almost any printable characters. Will not handle filenames containing a single-quote (but if you are moving those, it's time to go yell at whoever created them in the first place).

Rename all .jpeg and .JPG files to .jpg

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


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