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| -rw-r--r-- | libblkid/libblkid.3 | 79 |
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diff --git a/libblkid/libblkid.3 b/libblkid/libblkid.3 new file mode 100644 index 000000000..58ca91cbb --- /dev/null +++ b/libblkid/libblkid.3 @@ -0,0 +1,79 @@ +.\" Copyright 2001 Andreas Dilger (adilger@turbolinux.com) +.\" +.\" This man page was created for libblkid.so.1.0 from e2fsprogs-1.24. +.\" +.\" This file may be copied under the terms of the GNU Lesser General Public +.\" License. +.\" +.\" Created Wed Sep 14 12:02:12 2001, Andreas Dilger +.TH LIBBLKID 3 "May 2009" "util-linux" "Programmer's Manual" +.SH NAME +libblkid \- block device identification library +.SH SYNOPSIS +.B #include <blkid.h> +.sp +.B cc +.I file.c +.B \-lblkid +.SH DESCRIPTION +The +.B libblkid +library is used to identify block devices (disks) as to their content (e.g. +filesystem type) as well as extracting additional information such as +filesystem labels/volume names, unique identifiers/serial numbers. +A common use is to allow use of LABEL= and UUID= tags instead of hard-coding +specific block device names into configuration files. +.P +The low-level part of the library also allows to extract information about +partitions and block device topology. +.P +The high-level part of the library keeps information about block devices in a +cache file and is verified to still be valid before being returned to the user +(if the user has read permission on the raw block device, otherwise not). +The cache file also allows unprivileged users (normally anyone other +than root, or those not in the "disk" group) to locate devices by label/id. +The standard location of the cache file can be overridden by the +environment variable BLKID_FILE. +.P +In situations where one is getting information about a single known device, it +does not impact performance whether the cache is used or not (unless you are +not able to read the block device directly). +.P +The high-level part of the library supports two methods to evaluate LABEL/UUID. +It reads information directly from a block device or read information from +/dev/disk/by-* udev symlinks. The udev is preferred method by default. +.P +If you are dealing with +multiple devices, use of the cache is highly recommended (even if empty) as +devices will be scanned at most one time and the on-disk cache will be +updated if possible. +.P +In some cases (modular kernels), block devices are not even visible until +after they are accessed the first time, so it is critical that there is +some way to locate these devices without enumerating only visible devices, +so the use of the cache file is +.B required +in this situation. +.SH CONFIGURATION FILE +The standard location of the +.I /etc/blkid.conf +config file can be overridden by the environment variable BLKID_CONF. For more +details about the config file see +.BR blkid (8) +man page. +.SH AUTHOR +.B libblkid +was written by Andreas Dilger for the ext2 filesystem utilties, with input +from Ted Ts'o. The library was subsequently heavily modified by Ted Ts'o. + +The low-level probing code was rewritten by Karel Zak. +.SH COPYING +.B libblkid +is available under the terms of the GNU Library General Public License (LGPL), +version 2 (or at your discretion any later version). +.SH "SEE ALSO" +.BR blkid (8), +.BR findfs (8) +.SH AVAILABILITY +libblkid is part of the util-linux package since version 2.15 and is available from +ftp://ftp.kernel.org/pub/linux/utils/util-linux/. |