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Checks HDD for bad sectors, just like scandisk or chkdisk under some other operating system ;-).
With the "--resolve" switch, you can avoid doing DNS lookups or edit the /etc/hosts file, by providing the IP address for a domain directly. Useful if you have many servers with different IP addresses behind a load balancer. Of course, you would loop it:
$ for IP in 10.11.0.{1..10}; do curl --resolve subdomain.example.com:80:$IP subdomain.example.com -I -s; done
credit to tumblr engineering blog @ http://engineering.tumblr.com/
Useful to get network access to a machine behind shared IP NAT. Assumes you have an accessible jump host and physical console or drac/ilo/lom etc access to run the command.
Run the command on the host behind NAT then ssh connect to your jump host on port 2222. That connection to the jump host will be forwarded to the hidden machine.
Note: Some older versions of ssh do not acknowledge the bind address (0.0.0.0 in the example) and will only listen on the loopback address.
Run "ps -x" (process status) in the background every hour (in this example).
The outputs of both "nohup" and "ps -x" are sent to the e-mail (instead of nohup.out and stdout and stderr).
If you like it, replace "ps -x" by the command of your choice, replace 3600 (1 hour) by the period of your choice.
You can run the command in the loop any time by killing the sleep process. For example
$ ps -x
2925 ? S 0:00.00 sh -c unzip E.zip >/dev/null 2>&1
11288 ? O 0:00.00 unzip E.zip
25428 ? I 0:00.00 sleep 3600
14346 pts/42- I 0:00.01 bash -c while true; do ps -x | mail (...); sleep 3600; done
643 pts/66 Ss 0:00.03 -bash
14124 pts/66 O+ 0:00.00 ps -x
$ kill 25428
You have mail in /mail/(...)
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
No need for the ls -r and a sort is also not really needed.
Listens for events in the directory. Each created file is displayed on stdout. Then each fileline is read by the loop and a command is run.
This can be used to force permissions in a directory, as an alternative for umask.
More details:
http://en.positon.org/post/A-solution-to-the-umask-problem%3A-inotify-to-force-permissions
