Commands using printf (206)

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Delete all non-printing characters from a file
tr has some predefined sets of characters that are more convenient to use than characters codes

Optimize PDF documents

Download file with multiple simultaneous connections
`aria2c` (from the aria2 project) allows. Change -s 4 to an arbitrary number of segments to control the number of concurrent connections. It is also possible to provide multiple URLs to the same content (potentially over multiple protocols) to download the file concurrently from multiple hosts.

Generate random valid mac addresses
Ruby version. Also, a perl version: $perl -e 'printf("%.2x.",rand(255))for(1..5);printf("%.2x\n",rand(255))'

show git logging
shows some logging for the git repo.

Find top 10 largest files in /var directory (subdirectories and hidden files included )
Should work even when very large files exist.

Copy specific files to another machine, keeping the file hierarchy
Notes: * Adjust the find command to your own filters. * The -P flag forces to keep absolute paths in the tarball, so that you can be sure that the exact same file hierarchy will be created on the second machine.

Identify differences between directories (possibly on different servers)
This can be much faster than downloading one or both trees to a common servers and comparing the files there. After, only those files could be copied down for deeper comparison if needed.

how many packages installed on your archlinux?

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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