On: Use ack instead of grep to parse text files

[nene]

Maybe it's because you can write the latter also with plain grep:

    grep 'silver.*needle' haystack

[Firehed → nene]

That assumes that "silver" will appear before "needle", which may not always be the case. `grep needle file | grep silver` gets you lines containing both "silver" and "needle" but not necessarily in that order.