Automatic line numbering

Ever wanted to include a piece of code somewhere, and also have line numbers in order to have something to refer to when you’re discussing the code.

Use nl.

It’s another of those totally useful Unix utilities – short for line numbering filter. And it’s simple to use. Used as nl test.c, it just numbers all non-empty lines, however if all lines should be numbered,  the parameters can be modified to nl -ba test.c. This takes a file like this:

#include <stdio.h>

int main(void)
    int a, b;
    double d;

    if (a == b)
        d = a * b;
    return 0;

And turns it into this:

     1  #include <stdio.h>
     3  int main(void)
     4  {
     5      int a, b;
     6      double d;
     8      if (a == b)
     9          d = a * b;
    10      return 0;
    11  }





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