Commands by thisduck (3)

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Preserve colors when piping tree to less

Add a line from 1 file after every line of another (shuffle files together)
After every line in targetfile (empty lines included) insert in a line from addfile. "Save" results to savefile. Addfile should be longer than targetfile since this doesn't loop back to the top of addfile. /^/R addfile -- says for every line that matches "has a start of line" output a line from the file addfile. > savefile (optional) -- redirect output to savefile file.

Sort dotted quads
Sort a list of IPV4 addresses in numerical order. Great as a filter, or within vim using !}

Happy New Year!

Mount a partition from within a complete disk dump
Suppose you made a backup of your hard disk with dd: dd if=/dev/sda of=/mnt/disk/backup.img This command enables you to mount a partition from inside this image, so you can access your files directly. Substitute PARTITION=1 with the number of the partition you want to mount (returned from sfdisk -d yourfile.img).

analyze traffic remotely over ssh w/ wireshark
This captures traffic on a remote machine with tshark, sends the raw pcap data over the ssh link, and displays it in wireshark. Hitting ctrl+C will stop the capture and unfortunately close your wireshark window. This can be worked-around by passing -c # to tshark to only capture a certain # of packets, or redirecting the data through a named pipe rather than piping directly from ssh to wireshark. I recommend filtering as much as you can in the tshark command to conserve bandwidth. tshark can be replaced with tcpdump thusly: $ ssh [email protected] tcpdump -w - 'port !22' | wireshark -k -i -

ssh -A [email protected]
the -A argument forwards your ssh private keys to the host you're going to. Useful in some scenarios where you have to hop to one server, and then login to another using a private key.

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"

Add your public SSH key to a server in one command
Just run the command, type your password, and that's the last time you need to enter your password for that server. This assumes that the server supports publickey authentication. Also, the permissions on your home dir are 755, and the permissions on your .ssh dir are 700 (local and remote).

ruby one-liner to get the current week number


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