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Tiny Deathstars of Foulness

This New Years Day, Learn The Jot Command The jot command is one I haven’t used in awhile. But it’s still useful. Let’s take a look at a few of the things you can do with it. First, let’s just print lines into a new file called “century.txt” which we can do by running with the number of increments followed by the starting number, and then redirecting the output into the file name:

jot 100 1 > ~/Desktop/century.txt

Or to do integers instead, simply put the decimals:

jot 100 1.00 > ~/Desktop/century.txt

Or in descending order,

jot – 100 1 > ~/Desktop/century.txt

Now we could change the output to be just 50 to 100, by incrementing 50 (the first position) and starting at 50 (the second):

jot 50 50

The jot command is able to print sequential data, as we’ve seen. But we can also print random data, using the -r option. Following that option we have three important positions, the first is the number of iterations, but the next two are the lower and upper boundaries for the numbers, respectively. So in the below command we’ll grab 10 iterations (or ten random numbers) that are between 1 and 1000:

jot -r 10 1 1000

Now if we were to add a -c in there and use a and z as the upper and lower bounds, we’d get… letters (this time we’re just gonna’ ask for one letter)!

jot -r -c 1 a z

Something I find useful is just to shove random data into a file infinitely. And by useful I mean hopefully not left running overnight on my own computer (been there, done that). To do this, just use a 0 for the number of iterations:

jot -r -c 0

Something that is actually useful is the basic ASCII set:

jot -c 128 0

We can also append data to a word using -w. So let’s say we want to print the characters aa followed by a through z. In the below we’ll define that with -w and then we’ll list those two characters followed by %c which is where the character substitution goes and then the number of iterations followed by the lower bound:

jot -w aa%c 26 a

You can also do stuttering sequences, useful for the occasional tango dancer, so here we’ll do a 5/3 countdown:

jot – 100 0 -.5

Or we could create a one meg file by creating 1,024 bytes:

jot -b 0 1024 > onemegfile.txt

Oh wait, that file’s two megs. Get it? 😉

And running strings teaches you that you can’t bound random (a good lesson for the New Year). Anything you use jot for?

Happy New Years!

January 1st, 2018

Posted In: bash, Mac OS X, Mac OS X Server

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