Commands by ohuhu (0)

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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

Random Number Between 1 And 256
It takes a byte from /dev/random whose source is the kernel entropy pool (better source than other solutions).

Virtualbox rsync copy (without defining any virtualbox configuration)
That is, after running `vagrant ssh-config` to determine ports and ip's: $ vagrant ssh-config Host default HostName 127.0.0.1 User vagrant Port 2200 UserKnownHostsFile /dev/null StrictHostKeyChecking no PasswordAuthentication no IdentityFile /Users/romanvg/tmp/.vagrant/machines/default/virtualbox/private_key IdentitiesOnly yes LogLevel FATAL

Show exit status of all portions of a piped command eg. ls |this_doesn't_exist |wc

shut of the screen.

How To Get the Apache Document Root
Grabs the Apache config file (yielded from httpd) and returns the path specified as DocumentRoot.

list processes with established tcp connections (without netstat)
Uses lsof to list open network connections (file descriptors), grepping for only those in an established state

Nicely display mem usage with ps
Nicely display mem usage with ps.

find previously entered commands (requires configuring .inputrc)
[Click the "show sample output" link to see how to use this keystroke.]   Meta-p is one of my all time most used and most loved features of working at the command line. It's also one that surprisingly few people know about. To use it with bash (actually in any readline application), you'll need to add a couple lines to your .inputrc then have bash reread the .inputrc using the bind command:   $ echo '"\en": history-search-forward' >> ~/.inputrc   $ echo '"\ep": history-search-backward' >> ~/.inputrc   $ bind -f ~/.inputrc     I first learned about this feature in tcsh. When I switched over to bash about fifteen years ago, I had assumed I'd prefer ^R to search in reverse. Intuitively ^R seemed better since you could search for an argument instead of a command. I think that, like using a microkernel for the Hurd, it sounded so obviously right fifteen years ago, but that was only because the older way had benefits we hadn't known about.     I think many of you who use the command line as much as I do know that we can just be thinking about what results we want and our fingers will start typing the commands needed. I assume it's some sort of parallel processing going on with the linguistic part of the brain. Unfortunately, that parallelism doesn't seem to work (at least for me) with searching the history. I realize I can save myself typing using the history shortly after my fingers have already started "speaking". But, when I hit ^R in Bash, everything I've already typed gets ignored and I have to stop and think again about what I was doing. It's a small bump in the road but it can be annoying, especially for long-time command line users. Usually M-p is exactly what I need to save myself time and trouble.     If you use the command line a lot, please give Meta-p a try. You may be surprised how it frees your brain to process more smoothly in parallel. (Or maybe it won't. Post here and let me know either way. ☺)

Search and Replace across multiple files
- grep for the word in a files, use recursion (to find files in sub directories), and list only file matches -| xargs passes the results from the grep command to sed -sed -i uses a regular expression (regex) to evaluate the change: s (search) / search word / target word / g (global replace)


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