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function to verify an IP address - can be used at the shell prompt or in a shell script
When processing IP addresses in the shell (or shell script) it is useful to be able to verify that the value of data is an IP address (an not some random string or non-sensible IP address).

Speed up builds and scripts, remove duplicate entries in $PATH. Users scripts are oftern bad: PATH=/apath:$PATH type of thing cause diplicate.

get newest jpg picture in a folder
search the newest *.jpg in the directory an make a copy to newest.jpg. Just change the extension to search other files. This is usefull eg. if your webcam saves all pictures in a folder and you like the put the last one on your homepage. This works even in a directory with 10000 pictures.

use wget to check if a remote file exists

command shell generate random strong password
shell generate random strong password

Delete all but the latest 5 files, ignoring directories

Tail a log and replace according to a sed pattern
Tails a log and replaces it line-by-line according to whatever you want to replace. Useful if the file writing to the log can't be modified, so you need to modify its output instead.

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

Takes all file except file between !()
Go to tmp : cd /tmp; mkdir retmp; cd retmp Create 10 files : for i in {1..10}; do touch test$i; done Remove all files except test10 : rm !(test10)

Convert a string to "Title Case"
Converts the first letter of each word to upper case


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