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Remove text from file1 which is in file2 and stores it in an other file
This command compares file2 with file1 and removes the lines that are in file1 from file2. Handy if you have a file where file1 was the origional and you want to remove the origional data from your file2.

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

One liner to parse all epubs in a directory and use the calibre ebook-convert utility to convert them to mobi format
all ebook-convert -options are optional. all you really need to pass ebook-convert is the incoming and outgoing names, with extensions. Has been tested on Ubuntu 10.10

silent/shh - shorthand to make commands really quiet
Sometimes I just want to run a command quietly but all that keyboard shifting makes my fingers hurt. This little function does the job eg.: $ if shh type less; then PAGER=less; fi

Find the fastest server to disable comcast's DNS hijacking
Comcast is an ISP in the United States that has started hijacking DNS requests as a "service" for its customers. For example, in Firefox, one used to be able to do a quick "I'm Feeling Lucky" Google search by typing a single word into the URL field, assuming the word is not an existing domain when surrounded by www.*.com. Comcast customers never receive the correct NX (non-existent domain) error from DNS. Instead, they are shown a page full of advertising. There is a way to "opt out" from their service, but that requires having the account password and the MAC address of your modem handy. For me, it was easier just to set static DNS servers. But the problem is, which ones to choose? That's what this command answers. It'll show you the three _non-hijacked_ Comcast DNS servers that are the shortest distance away. Perhaps you don't have Comcast (lucky you!), but hopefully this command can serve as an example of using netselect to find the fastest server from a list. Note that, although this example doesn't show it, netselect will actually perform the uniq and DNS resolution for you. Requires: netselect, curl, sort, uniq, grep

Colorized grep in less
Get your colorized grep output in less(1). This involves two things: forcing grep to output colors even though it's not going to a terminal and telling less to handle those properly.

Annotate tail -f with timestamps

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

diff two svn repos ignoring spaces,tabs and svnfiles

Show a Package Version on Debian based distribution
if you don't want to show string "version?, then use awk or cut filter it: apt-cache show pkgname | grep -i "version:" | awk '{ print $2 }' we can also use regex to search many packages and show their versions: apt-cache search pkgregex | grep -i "version:"


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