Commands by shawnkemp (0)

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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 The command is untested under any other distros or less outdated kernels.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.

back ssh from firewalled hosts
host B (you) redirects a modem port (62220) to his local ssh. host A is a remote machine (the ones that issues the ssh cmd). once connected port 5497 is in listening mode on host B. host B just do a ssh -p 5497 -l user and reaches the remote host'ssh. This can be used also for vnc and so on.

Recursive grep of all c++ source under the current directory
I like this better than some of the alternatives using -exec, because if I want to change the string, it's right there at the end of the command line. That means less editing effort and more time to drink coffee.

Get the absolute path of a file

Get all mac address
I prefer the ip command to ifconfig as ifconfig is supposedly going to be deprecated. Certain IP address aliases can only be seen with the ip command (such as the ones applied by RHCS).

Copy your ssh public key to a server from a machine that doesn't have ssh-copy-id
If you use Mac OS X or some other *nix variant that doesn't come with ssh-copy-id, this one-liner will allow you to add your public key to a remote machine so you can subsequently ssh to that machine without a password.

Identify differences between directories (possibly on different servers)
This can be much faster than downloading one or both trees to a common servers and comparing the files there. After, only those files could be copied down for deeper comparison if needed.

Fast, built-in pipe-based data sink
This is shorter and actually much faster than >/dev/null (see sample output for timings) Plus, it looks like a disappointed face emoticon.

Quickly share code or text from vim to others. is a code/text sharing site like pastebin, but it is easy to post stuff from the command line. $ How it works: $ :w !command In vim, w writes the current tab to a file when a filename is given afterwards, but if !command is given, the output is piped to the stdin of command. $curl -F "sprunge=

Find and delete oldest file of specific types in directory tree
This works on my ubuntu/debian machines. I suspect other distros need some tweaking of sort and cut. I am sure someone could provide a shorter/faster version.

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