Commands using cat (504)

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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

Display unique values of a column
Find the unique values of a column utilizing awk. Credits goes to here (posted by "era"): http://www.unix.com/shell-programming-scripting/77138-awk-print-distinct-col-values.html

Print all the lines between 10 and 20 of a file
Similarly, if you want to print from 10 to the end of line you can use: sed -n '10,$p' filename This is especially useful if you are dealing with a large file. Sometimes you just want to extract a sample without opening the entire file. Credit goes to wbx & robert at the comments section of http://www.commandlinefu.com/commands/view/348/get-line1000-from-text.#comment

Create patch file for two directories

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"

Add prefix onto filenames
Best to try first with -n flag, to preview

Display your ${PATH}, one directory per line
This works in bash and zsh. You may also want to alias it, if you need to look at it often... $ alias lpath="echo \$PATH | tr : \\\\n" "\$PATH" to make sure to look at your current $PATH

Clean way of re-running bash startup scripts.
This replaces the current bash session with a new bash session, run as an interactive non-login shell... useful if you have changed /etc/bash.bashrc, or ~/.bashrc If you have changed a startup script for login shells, use $ exec bash -l Suitable for re-running /etc/profile, ~/.bash_login and ~/.profile. edit: chinmaya points out that $ env - HOME=$HOME TERM=$TERM bash -s "exec bash -l" will clear any shell variables which have been set... since this verges on unwieldy, might want to use $ alias bash_restart='env - HOME=$HOME TERM=$TERM bash -s "exec bash -l"'

Count number of files in a directory

How fast is the connexion to a URL, some stats from curl


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