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Show a config file without comments

Rename all files in a directory to the md5 hash

execute a shell with netcat without -e
Shorter version with proper stderr redirection .

Search for files in rpm repositorys. (Mandriva linux)
Look for an rpm that supplies a specific file that you don't yet have installed. extremely useful when you need something and don't know where it is.. or what its called. note: uses grep like syntax.

grep binary (hexadecimal) patterns
-P activates the Perl regular expression mode.

c_rehash replacement
When you don't have c_rehash handy. Really simple - if you have a .pem file that doesn't really contain a x509 cert (let's say, newreq.pem), it will create a link, simply called '.0', pointing to that file.

Find the real procesor speed when you use CPU scaling [cpuspeed]
We don't use CPU scaling, but just in case you do, there is something interesting to note. If you look at the /proc/cpuinfo, the speed listed is current running speed of the processors and not the real speed of the chip.

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

Remove duplicate rows of an un-sorted file based on a single column
$F[0] filters using first word. $F[1] - 2nd, and so on.

Emergency Alien Invasion Warning
When aliens invade Earth, be first to warn your neighbours by placing your computer screen at a window and executing this potentially Earth-saving command. Ctrl C when aliens are defeated.


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