Commands tagged expr (3)

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Convert files from DOS line endings to UNIX line endings
The old dos2unix from sysutils has been deprecated on Debian systems to this tool.

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

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"

Check RAM size
Check RAM size

Calculate days on which Friday the 13th occurs (inspired from the work of the user justsomeguy)
Friday is the 5th day of the week, monday is the 1st. Output may be affected by locale.

Bash autocomplete case insensitive search
Change bash autocomplete case search to insensitive when pressing tab for completion.

Anti Syn Ddos
Ddos syn attack

cd to (or operate on) a file across parallel directories
This is useful for quickly jumping around branches in a file system, or operating on a parellel file. This is tested in bash. cd to (substitute in PWD, a for b) where PWD is the bash environmental variable for the "working directory"

Process command output line by line in a while loop
This snippet allows to process the output of any bash command line by line.

Get list of servers with a specific port open
Change the -p argument for the port number. See "man nmap" for different ways to specify address ranges.


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