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This will perform one of two blocks of code, depending on the condition of the first. Essentially is a bash terniary operator.
To tell if a machine is up:
$ ping -c1 machine { echo succes;} || { echo failed; }
Because of the bash { } block operators, you can have multiple commands
$ ping -c1 machine && { echo success;log-timestamp.sh }|| { echo failed; email-admin.sh; }
Tips:
Remember, the { } operators are treated by bash as a reserved word: as such, they need a space on either side.
If you have a command that can fail at the end of the true block, consider ending said block with 'false' to prevent accidental execution
I often use it to find recently added ou removed device, or using find in /dev, or anything similar.
Just run the command, plug the device, and wait to see him and only him
Using this command you can track a moment when usb device was attached.
This assumes you have the package installed necessary for converting WMF files. On my Ubuntu box, this is libwmf-bin. I used this command, as libwmf is not on my wife's iMac, so I archived the directories containing the WMF files from OS X, ran them on my Ubuntu box, archived the resulting SVGs, and sent them back to her. Quick, simple and to the point.
Searches directories recursively looking for extensions ignoring case. This is much more readable and clean than -exec for find. The while loop also gives further flexibility on complex logic. Also, although there is 'wmf2svg --auto', it expects lowercase extensions, and not uppercase. Because I want to ignore case, I need to use the -o option instead.
Works in ZSH and BASH. Haven't tested in other shells.
This is an alternative to another command using two xargs. If it's a command you know there's only one of, you can just use:
$ ls -l /proc/$(pgrep COMMAND)/cwd
PDF files are simultaneously wonderful and heinous. They are wonderful in being ubiquitous and mostly being cross platform. They are heinous in being very difficult to work with from the command line, search, grep, use only the text inside the PDF, or use outside of proprietary products.
xpdf is a wonderful set of PDF tools. It is on many linux distros and can be installed on OS X. While primarily an open PDF viewer for X, xpdf has the tool "pdftotext" that can extract formated or unformatted text from inside a PDF that has text. This text stream can then be further processed by grep or other tool. The '-' after the file name directs output to stdout rather than to a text file the same name as the PDF.
Make sure you use version 3.02 of pdftotext or later; earlier versions clipped lines.
The lines extracted from a PDF without the "-layout" option are very long. More paragraphs. Use just to test that a pattern exists in the file. With "-layout" the output resembles the lines, but it is not perfect.
xpdf is available open source at http://www.foolabs.com/xpdf/