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check open ports without netstat or lsof

Printout a list of field numbers (awk index) from a CSV file with headers as first line.
Useful to identify the field number in big CSV files with large number of fields. The index is the reference to use in processing with commands like 'cut' or 'awk' involved.

Command line calculator
This function defines a command line calculator that handles everything pythons math module can handle, e.g. trigonometric functions, sqrt, log, erf, ... (see http://docs.python.org/library/math.html). It even knows about the constants pi and e.

how many packages installed on your archlinux?

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

List files older than one year, exluding those in the .snapshot directory
Useful when you want to cron a daily deletion task in order to keep files not older than one year. The command excludes .snapshot directory to prevent backup deletion. One can append -delete to this command to delete the files : $ find /path/to/directory -not \( -name .snapshot -prune \) -type f -mtime +365 -delete

Get a range on line with sed (first two)
Get the two first lines of a file and quit.

Block all IP addresses and domains that have attempted brute force SSH login to computer
I use iptables. To rate limit connections. Very easy and no ban lists to manage.

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

grep certain file types recursively
doesn't do case-insensitive filenames like iname but otherwise likely to be faster


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