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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"

Convert (almost) any video file into webm format for online html5 streaming

Remove blank lines from a file using grep and save output to new file
The ^$ within the quotes is a regular expression: ^=beginning of line, $=end of line, with no characters between.

most used unix commands

Clear all Windows Event Log entries (cygwin)
Efficiently clear all Windows Event log entries from within a Cygwin terminal. Uses "cygstart" to launch a hidden "PowerShell" session passing a Powershell command to loop through and clear all Windows Event Log entries. Very useful for troubleshooting and debugging. The command should in theory elevate you session if needed. One liner is based on the PowerShell command: $ wevtutil el | foreach { wevtutil cl $_ }

Shows size of dirs and files, hidden or not, sorted.
Very useful when you need disk space. It calculates the disk usage of all files and dirs (descending them) located at the current directory (including hidden ones). Then sort puts them in order.

diff will usually only take one file from STDIN. This is a method to take the result of two streams and compare with diff. The example I use to compare two iTunes libraries but it is generally applicable.
diff is designed to compare two files. You can also compare directories. In this form, bash uses 'process substitution' in place of a file as an input to diff. Each input to diff can be filtered as you choose. I use find and egrep to select the files to compare.

After typing lots of commands in windows, save them to a batch file quickly
After typing the command below, you will be greeted with nothing. press the up arrow to find the previous command you typed, press enter. repeat this as many times as you need, then hit CTRL-Z and press enter to save to the 'batchfilename.bat' file.

Get AWS temporary credentials ready to export based on a MFA virtual appliance
You might want to secure your AWS operations requiring to use a MFA token. But then to use API or tools, you need to pass credentials generated with a MFA token. This commands asks you for the MFA code and retrieves these credentials using AWS Cli. To print the exports, you can use: `awk '{ print "export AWS_ACCESS_KEY_ID=\"" $1 "\"\n" "export AWS_SECRET_ACCESS_KEY=\"" $2 "\"\n" "export AWS_SESSION_TOKEN=\"" $3 "\"" }'` You must adapt the command line to include: * $MFA_IDis ARN of the virtual MFA or serial number of the physical one * TTL for the credentials

Backup with versioning
Apart from an exact copy of your recent contents, also keep all earlier versions of files and folders that were modified or deleted. Inspired by EVACopy http://evacopy.sourceforge.net


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