Commands by RandyNelson (0)

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Console clock
Turn your terminal into digital clock.

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"

Control ssh connection
SSH can be controlled trough an ~ escape sequence. Example, to terminate the current ssh connection, type a newline, then the ~ character, and last a . character. This is useful eg when an ssh connection hangs after you reboot a machine and the connection hangs.

Start another X session in a window
You might have Xnest (older) rather than Xephyr. You can experiment with other desktops eg: startx /usr/bin/start-kde -- /usr/bin/Xephyr :2 You can start X on a remote machine (although I'd recommend vnc for anything slower than a LAN): startx /usr/bin/ssh -X gnome-session -- /usr/bin/Xephyr :2 Or just start another X session locally talking to the remote backend:

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"

Stop long commands wrapping around and over-writing itself in the Bash shell
add the command either in /etc/profile or ~/.bash_profile so that this is available to your shell.

Show top 50 running processes ordered by highest memory/cpu usage refreshing every 1s
http://alvinalexander.com/linux/unix-linux-process-memory-sort-ps-command-cpu for an overview of --sort available values

Take a file as input (two columns data format) and sum values on the 2nd column for all lines that have the same value in 1st column
Example: $ cat

Run remote web page, but don't save the results
I have a remote php file that I want to run once an hour. I set up cron to run this wget. I don't really care about what's in the file though, I don't want to save the results, so I run the -O and send it to /dev/null

Make a server's console beep when the network is down
This is like ping -a, but it does the opposite. It alerts you if the network is down, not up. Note that the beep will be from the speaker on the server, not from your terminal. Once a second, this script checks if the Internet is accessible and beeps if it is not. I define the Net as being "UP", if I can ping Google's public DNS server (8.8.8.8), but of course you could pick a different static IP address. I redirect the beep to /dev/console so that I can run this in the background from /etc/rc.local. Of course, doing that requires that the script is run by a UID or GID that has write permissions to /dev/console (usually only root). Question: I am not sure if the -W1 flag works under BSD. I have only tested this under GNU/Linux using ping from iputils. If anybody knows how portable -W is, please post a comment.

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