How do I keep a line number count when using reader.eachLine to read a BufferedInputStream?

Question

How can I keep track of the line number I'm on when using eachLine to read a BufferedInputStream?

def input = new GZIPInputStream(new FileInputStream(f))
def reader = new BufferedReader(new InputStreamReader(input))
reader.eachLine {
    line ->if(line.contains(searchString)){
        println "${f} - ${line}"
    }
}

Answer 1

The closure you pass to eachLine can also take 2 parameters. First being the line of data and the second being the line number.

....
....
reader.eachLine { line, lineNumber ->
    if(line.contains(searchString)) {
        println "${lineNumber} - ${line}"
    }
}

See GDK Doc for InputStream eachLine method