Commands by javidjamae (3)

What's this? is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

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Generate a binary file with all ones (0xff) in it
This is similar to how you would generate a file with all zeros $ dd if=/dev/zero of=allzeros bs=1024 count=2k

Show top running processes by the number of open filehandles they have
I think I could cut down the number of pipes here, any suggestions?

Look up a unicode character by name
No need for further filedes or substitution for splitting. Simply use read a b

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

Find usb device in realtime
Using this command you can track a moment when usb device was attached.

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"

Count opening and closing braces in a string.
This function counts the opening and closing braces in a string. This is useful if you have eg long boolean expressions with many braces and you simply want to check if you didn't forget to close one.

Use a var with more text only if it exists
See "Parameter Expansion" in the bash manpage. They refer to this as "Use Alternate Value", but we're including the var in the at alternative.

Git diff last two commits
How about this one ?

Look up the definition of a word
A bash function might also be useful: $ dict() { curl dict://$1; } Or if you want less verbose output: $ dict() { curl -s dict://$1 | perl -ne 's/\r//; last if /^\.$/; print if /^151/../^250/'; }

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