On Wed, Apr 18, 2007 at 03:27:09PM +0100, Neil Williams wrote: > On Wed, 18 Apr 2007 16:53:38 +0300 > Peter Pentchev <roam@ringlet.net> wrote: > > > truncate - FreeBSD utility to truncate or extend the size of files > > > > The truncate utility adjusts the length of each regular file given > > on the command-line. This package is simply a redistribution of the > > utility as found in the FreeBSD base system. > > That description doesn't help explain why a file would need to be > truncated (or extended without allocating space). Why truncate a file > (and lose data) rather than split the file? Why extend a file > without allocating space? Most (all?) file->open routines will support > complete truncation to zero length, what is the advantage of retaining > only a portion of the old data in the file and risk losing data > integrity (because not all regular files use linear storage). > XML/HTML/SGML are just three common regular file types that will react > badly to arbitrary truncation and ignore extended file sizes without > adding data. > > Don't assume that users will know anything about the FreeBSD version - > you need to explain the what, why and when of using such a program > without reference to assumptions based on *BSD. Argh. Yep, come to think of it, this brief description could be kinda misread this way :) Actually, the reference to FreeBSD was more of a recognition of the truncate original authors, not a usage reference or anything - but you're right, in the absence of any usage references at all... Actually, the reason that pushed me to port truncate(1) to Debian was the need to create a large empty file while tracking down a problem with a webserver's large file support. Other than that, I've used it to initialize loopback-mount filesystems, maim lastlog files and news spool indices by only leaving the headers, and "sudo truncate -s0 file" as an easier-on-the-fingers alias for "sudo sh -c ': > file'" :) So... what do you think about the following description? Or should I file a wishlist bug against bsdmainutils to get truncate(1) included there? The truncate utility adjusts the length of each regular file given on the command-line. It may be used to create sparse files (zero-filled files that do not take up any space on disk) for virtual filesystems, empty data files, or simply large files for testing. It may also empty a file by setting its size to 0 bytes, or remove all but a portion of the data, most useful when the file has a well-known record-based structure like e.g. filesystem images, news spools, utmp or sa(8) accounting files, graphics images, etc. . This package is simply a redistribution of the truncate utility as found in the FreeBSD base system. . Homepage: http://devel.ringlet.net/sysutils/truncate/ Thank you and the others for the prompt replies and comments! G'luck, Peter -- Peter Pentchev roam@ringlet.net roam@cnsys.bg roam@FreeBSD.org PGP key: http://people.FreeBSD.org/~roam/roam.key.asc Key fingerprint FDBA FD79 C26F 3C51 C95E DF9E ED18 B68D 1619 4553 because I didn't think of a good beginning of it.
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