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diff will usually only take one file from STDIN. This is a method to take the result of two streams and compare with diff. The example I use to compare two iTunes libraries but it is generally applicable.
diff is designed to compare two files. You can also compare directories. In this form, bash uses 'process substitution' in place of a file as an input to diff. Each input to diff can be filtered as you choose. I use find and egrep to select the files to compare.

underscore to camelcase

set your screensaver as your desktop background MAC OSX

Find unused IPs on a given subnet

Short Information about loaded kernel modules

Get IPv4 of eth0 for use with scripts
I've been using it in a script to build from scratch proxy servers.

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

List all files modified by a command
Often you run a command, but afterwards you're not quite sure what it did. By adding this prefix/suffix around [COMMAND], you can list any files that were modified. . Take a nanosecond timestamp: YYYY-MM-DD HH:MM:SS.NNNNNNNNN $ date "+%F %T.%N" . Find any files that have been modified since that timestamp: $ find . -newermt "$D" . This command currently only searches below the current directory. If you want to look elsewhere change the find parameter, e.g. $ find /var/log . -newermt "$D"

View Owner, Group & Permissions.
#Alias alias perm="stat -c '%n %U:%G-%a'" #Function perm() { for ll in $@; do stat -c "%n %U:%G-%a" "$ll"; done; }

a function to find the fastest DNS server
http://public-dns.info gives a list of online dns servers. you need to change the country in url (br in this url) with your country code. this command need some time to ping all IP in list.


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