Commands by rwunsch (1)

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Determine MAC address of remote host when you know its IP address
arping sends ARP requests to a neighboring host. This won't work if there is an ARP subnet gateway in the middle. If there is, you'll just get the gateway's MAC address not the host's address you are really trying to get to.

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"

list block devices
Shows all block devices in a tree with descruptions of what they are.

Virtualbox rsync copy (without defining any virtualbox configuration)
That is, after running `vagrant ssh-config` to determine ports and ip's: $ vagrant ssh-config Host default HostName 127.0.0.1 User vagrant Port 2200 UserKnownHostsFile /dev/null StrictHostKeyChecking no PasswordAuthentication no IdentityFile /Users/romanvg/tmp/.vagrant/machines/default/virtualbox/private_key IdentitiesOnly yes LogLevel FATAL

List only the directories
-d: list directory entries instead of contents, and do not dereference symbolic links

Check if the Debian package was used since its installation/upgrade.
This script compares the modification date of /var/lib/dpkg/info/${package}.list and all the files mentioned there. It could be wrong on noatime partitions. Here is non-oneliner: #!/bin/sh package=$1; list=/var/lib/dpkg/info/${package}.list; inst=$(stat "$list" -c %X); cat $list | ( while read file; do if [ -f "$file" ]; then acc=$(stat "$file" -c %X); if [ $inst -lt $acc ]; then echo used $file exit 0 fi; fi; done exit 1 )

Quickly graph a list of numbers
Useful when you've produced a large file of numbers, and want to quickly see the distribution. The value of y halfway along the x axis is the median. Simple! Just create the listOfNumbers.txt file with a number on each line to try it out.

Find directories under home directory with 777 permissions, change to 755, and list them on console

Floating point power p of x
One pipe less.

Display the history and optionally grep
Place this in your .bash_profile and you can use it two different ways. If you issue 'h' on its own, then it acts like the history command. If you issue: $ h cd Then it will display all the history with the word 'cd'

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