Re: [Help-bash] how to grep the last match out from a bunch of files

[lina]

On Wednesday 28,December,2011 01:12 AM, Greg Wooledge wrote:
> On Wed, Dec 28, 2011 at 01:03:33AM +0800, lina wrote:
> > I have a bunch of files like a_*.txt
> >
> > it contains many "step" in a_*.txt
> >
> > $ cat a_1.txt
> > step
> > 1
> > step
> > 2
> > step
> > 3
> > some lines appended here
> > I wish to get the final step,
> > for a_1.txt it's 3
> awk '/^step$/ {getline; step=$0} END {print step}'

Thanks for you quick reply,

sorry, too concise for me to be able to put into practice about the 
bunch of files part.

$ more try.sh
#!/usr/bin/awk

awk 'BEGIN{
    /^step$/
    }
    {
    getline;
    step=$0
    }
END{
    print step
}' $0

$ ./try.sh a_*.txt
awk: ./try.sh
awk: ^ syntax error
awk: ./try.sh
awk:   ^ unterminated regexp

Thanks ahead with best regards,

> It could be made more efficient, e.g. by skipping all the rest of the
> reads when you don't match ^step$, but that will suffice for a teaching
> example.
>
> Awk reads input line by line, and applies checks/actions to each line.
> I told it to act when it sees a line that matches the regular expression
> pattern ^step$.  When it matches, it will read the next line from the
> input ("getline"), and then set the "step" variable to the content of that
> line.  It keeps doing that until there are no more lines.
>
> Then at the END of the input, it prints the contents of the step variable.