Commands tagged inotify (5)

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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

Copy input sent to a command to stderr
In the above example 'muspi merol' (the output of the first rev command) is sent to stderr and 'lorem ipsum' (the output of the second rev command) is sent to stdout. rev reverse lines of a file or files. This use of tee allows testing if a program correctly handles its input without using files that hold the data.

find and delete files smaller than specific size

Backticks are evil
This is a simple example of using proper command nesting using $() over ``. There are a number of advantages of $() over backticks. First, they can be easily nested without escapes: $ program1 $(program2 $(program3 $(program4))) versus $ program1 `program2 \`program3 \`program4\`\`` Second, they're easier to read, then trying to decipher the difference between the backtick and the singlequote: `'. The only drawback $() suffers from is lack of total portability. If your script must be portable to the archaic Bourne shell, or old versions of the C-shell or Korn shell, then backticks are appropriate, otherwise, we should all get into the habit of $(). Your future script maintainers will thank you for producing cleaner code.

Check if it's OK to spawn tmux. Bool's Rools.
The command cechks if we are connected to a X11 console, if the $TERM var noct yet contains a "screen" derivat, and only then attachs to tmux. You could add a test for interactive shell [[ $- == *i* ]] but your .bashrc has that already, I bet.

List all files in current dir and subdirs sorted by size
or $ tree -ifsF --noreport .|sort -n -k2|grep -v '/$' (rows presenting directory names become hidden)

convert doc to pdf
convert to pdf and many other formats and vise versa to get a list of supported formats, run $ unoconv --show

Scan Subnet for IP and MAC addresses

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. ☺)

Delay execution until load average falls under 1.5
If shell escaping of the command is problematic, you can write the command to a file first: $ batch


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