Christian Seiler <christ...@iwakd.de> writes:
> On 08/01/2016 02:52 PM, Rodolfo Medina wrote:
>> with the following simple script:
>>
>> #!/bin/sh
>>
>> cat index.idx | sort > index.ind
>>
>> I sort the contents of a file and write it in another file. Now, I want
>> that a small vertical space, i.e. an empty line or two, were inserted before
>> all the words that start with a new letter.
>
> If the first letters of your words are only ASCII characters
> (or you are using an 8 bit character encoding), then the
> following should do the trick:
>
> sort < index.idx | awk 'BEGIN {
> c = -1;
> }
> {
> if (substr($0, 1, 1) != c && c != -1)
> printf("\n\n");
> c = substr($0, 1, 1);
> print;
> }' > index.ind
>
> See also:
> https://en.wikibooks.org/wiki/AWK
Thanks indeed, it works fine.
Rodolfo
