Simple bash script to print prime numbers from 1 to 1000

Question

How can I make a POSIX script that will print all the prime numbers from 1 to 1000?

Solution

factor {2..1000} | awk 'NF==2{print $2}'

Comments

[Shadur]

You'll want python or perl for that, bash isn't exactly a good choice for math stuff.

[Allan]

This sounds like something you needed for a class. Shouldn't you have at least made an initial attempt yourself and ask for assistance rather than just asking outright for the answer? How do you move forward from newbie if you don't try?

[Stéphane Chazelas]

@Shadur, the OP asked for a POSIX script, not bash. POSIX comes with several utilities that can be used as script interpreters like awk, bc, sh, sed. awk and bc are perfectly suited for the task or could be invoked from a sh script. A shell is primarily a command line interpreter, so if any command can do the task, any shell script that invokes that command (which could by perl or python) would work.

[FranceskaSophie]

Thanks for the reply! Helped me a lot, but I'm not quite sure how to interpret that code. Would you care to explain to me how it works? I was thinking of using a "for"

[orion]

The point of a shell is to glue together existing pieces of purpose made things that do one thing, and do it well. In this case, I'm calling factor which factorizes numbers and awk is there just to filter the output (only print if there is only one factor). If your goal was to write the prime algorithm from scratch, then you'll probably have loops and such. But that, you can try for yourself.

[Stéphane Chazelas]

factor is not a POSIX command.