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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

Follow tail by name (fix for rolling logs with tail -f)
If you use 'tail -f foo.txt' and it becomes temporarily moved/deleted (ie: log rolls over) then tail will not pick up on the new foo.txt and simply waits with no output. 'tail -F' allows you to follow the file by it's name, rather than a descriptor. If foo.txt disappears, tail will wait until the filename appears again and then continues tailing.

Another Matrix Style Implementation

Configuring proxy client on terminal without leaving password on screen or in bash_history
Prompts the user for username and password, that are then exported to http_proxy for use by wget, yum etc Default user, webproxy and port are used. Using this script prevent the cleartext user and pass being in your bash_history and on-screen

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

Watch the progress of 'dd'
The previously-posted one-liner didn't work for me for whatever reason, so I ended up doing this instead.

List the Sizes of Folders and Directories

Arguments too long

Generate random valid mac addresses
Ruby version. Also, a perl version: $perl -e 'printf("%.2x.",rand(255))for(1..5);printf("%.2x\n",rand(255))'

Adding formatting to an xml document for easier reading
Sometimes you're trying to read through an xml file to determine whats wrong with it and a tool had removed all the linebreaks. xmllint will go ahead and make it pretty for you.


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