help with pipes

Gilles Espinasse g.esp at
Sun Feb 22 00:43:20 PST 2009

----- Original Message ----- 
From: "Robert Connolly" <robert at>
To: "Hardened LFS Development List" <hlfs-dev at>
Sent: Sunday, February 22, 2009 3:13 AM
Subject: help with pipes

> Hello. As mentioned before, I have a problem with:
> bzcat ../loop-AES-v3.2e-20090112.diff.bz2 | patch -p1 &&
> The && is useless because of the |. I think the && is using the return
> from bzcat, and not from patch. Redirection would work, except that the
> is bzip2 compressed. For example:
> patch -p1 < ../loop-AES-v3.2e-20090112.diff
> works, but
> patch -p1 < $(bzcat ../loop-AES-v3.2e-20090112.diff.bz2)
> does not (ambiguous redirect).
> Is there another way, aside from decompressing the patch in the sources
> directory?
that work
bzcat ../loop-AES-v3.2e-20090112.diff.bz2 | (patch -p1 && echo ok)

echo ok is just there as a visual check to verify && work as intended.
openswan was using a similar construction to patch the kernel on previous
that was more like | (cd $(DIR_APP) && patch -p1) and when I forgot the (),
nothing was done.



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