Commands by narven (4)

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determine if tcp port is open
for udp nmap -sU -p 80 hostname

Backticks are evil
This is a simple example of using proper command nesting using $() over ``. There are a number of advantages of $() over backticks. First, they can be easily nested without escapes: $ program1 $(program2 $(program3 $(program4))) versus $ program1 `program2 \`program3 \`program4\`\`` Second, they're easier to read, then trying to decipher the difference between the backtick and the singlequote: `'. The only drawback $() suffers from is lack of total portability. If your script must be portable to the archaic Bourne shell, or old versions of the C-shell or Korn shell, then backticks are appropriate, otherwise, we should all get into the habit of $(). Your future script maintainers will thank you for producing cleaner code.

print only matched pattern
Print only the matched pattern at the console

Get memory total from /proc/meminfo in Gigs

Colored status of running services
Replace service --status-all 2>&1 by service --status-all 2>/dev/null to hide all services with the status [ ? ]

Create a html of information about you harddisk
www.fir3net.com

exit if another instance is running

Find the package that installed a command

dd with progress bar and statistics
Uses the pv utility to show progress of data transfer and an ETA until completion. You can install pv via Homebrew on macOS

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


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