Pádraig Brady wrote: > On 23/11/10 16:24, Stefan Tomanek wrote: >> Dies schrieb Stefan Tomanek (stefan.toma...@wertarbyte.de): >> >>> It is often convinient to detect whether head has in fact printed the >>> requested number of lines or if EOF was reached before reaching that >>> point. This patch adds the option --indicate-underrun, which makes >>> "head" exit with a status of 4 instead of 0 if no more data could be >>> read from its input. >> >> Any thoughts about this change? It's a rather small patch, but would >> be quite useful (at least for me). > > This does seem useful on the face of it. > I need to do a little further investigation > to see if there are existing ways to achieve the same.
For the record, here's a quick one-liner: $ seq 2|perl -ne '$n=3; print; $.==$n and $ok=1,last; END{exit 4*!!$ok}' 1 2 $ seq 5|perl -ne '$n=3; print; $.==$n and $ok=1,last; END{exit 4*!!$ok}' 1 2 3