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Monitoring wifi connection by watch command (refresh every 3s), displaying iw dump info and iwconfig on wireless interface "wlan0"

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"

Copy via tar pipe while preserving file permissions (cp does not!; run this command with root!)
cp options: -p will preserve the file mode, ownership, and timestamps -r will copy files recursively also, if you want to keep symlinks in addition to the above: use the -a/--archive option

List files accessed by a command
Can be run as a script `ftrace` if my_command is substrituted with "$@" It is useful when running a command that fails and you have the feeling it is accessing a file you are not aware of.

Buffer in order to avoir mistakes with redirections that empty your files
A common mistake in Bash is to write command-line where there's command a reading a file and whose result is redirected to that file. It can be easily avoided because of : 1) warnings "-bash: file.txt: cannot overwrite existing file" 2) options (often "-i") that let the command directly modify the file but I like to have that small function that does the trick by waiting for the first command to end before trying to write into the file. Lots of things could probably done in a better way, if you know one...

Disassemble some shell code
This one liner takes the shell code that you can grab off of the web and disassemble it into readable assembly so you can validate the code does what it says, before using it. The shell code in the above example is from http://www.shell-storm.org/shellcode/files/shellcode-623.php You can replace "-s intel" with "-s att" to get AT&T format disassembly.

find files ignoring .svn and its decendents

Quickly ping range of IP adresses and return only those that are online
Tested in Debian, ymmv. - c 1 : send only one ping;; -W 1: wait for one second and then exit ping, assuming target IP is not available; change as needed (-W 0.5 for half a second, smaller or greater value depending on network speed/latency)

vi a remote file
notice the double slash

Do a search-and-replace in a file after making a backup


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