Date: Wed, 17 Nov 2010 13:55:21 -0600 From: Dan Nelson <dnelson@allantgroup.com> To: Alexander Best <arundel@freebsd.org> Cc: freebsd-questions@freebsd.org Subject: Re: a question regarding proper printf(3) formating and alignment Message-ID: <20101117195521.GF57869@dan.emsphone.com> In-Reply-To: <20101117155006.GA88394@freebsd.org> References: <20101117155006.GA88394@freebsd.org>
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In the last episode (Nov 17), Alexander Best said: > hi there, > > i've looked at a lot of utilities in the bsd src tree and most of them > seem to be doing something like this: > > Device 1M-blocks Used Avail Capacity > /dev/label/swapfs 10239 0 10239 0% > /dev/label/swap 8191 0 8191 0% > Total 18431 0 18431 0% > > as you can see the header simply gets written with a number of tabs in > between the keywords, but then the actual output aligns differently. > > i'd like to learn of ways formatting the header so that it aligns > properly, whether the device name is 10 chars long or 1000. is there an > example for this somewhere in the src tree? /bin/ls does this for the user, group, and size columns. Note that this only works if you batch up your output (or take two passes over your input data). I seem to remember /usr/bin/find doing this dynamically by expanding columns as it saw values that were larger than the previous max, but apparently not (I just tested it). -- Dan Nelson dnelson@allantgroup.com
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