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Diffstat (limited to 'sys-utils/losetup.8')
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diff --git a/sys-utils/losetup.8 b/sys-utils/losetup.8 new file mode 100644 index 0000000..9b5fe61 --- /dev/null +++ b/sys-utils/losetup.8 @@ -0,0 +1,174 @@ +.TH LOSETUP 8 "July 2003" "util-linux" "System Administration" +.SH NAME +losetup \- set up and control loop devices +.SH SYNOPSIS +.ad l +Get info: +.sp +.in +5 +.B losetup +.I loopdev +.sp +.B losetup -a +.sp +.B losetup -j +.I file +.RB [ \-o +.IR offset ] +.sp +.in -5 +Delete loop: +.sp +.in +5 +.B "losetup \-d" +.IR loopdev ... +.sp +.in -5 +Delete all used loop devices: +.sp +.in +5 +.B "losetup \-D" +.sp +.in -5 +Print name of first unused loop device: +.sp +.in +5 +.B "losetup \-f" +.sp +.in -5 +Setup loop device: +.sp +.in +5 +.B losetup +.RB [{ \-e | \-E } +.IR encryption ] +.RB [ \-o +.IR offset ] +.RB [ \-\-sizelimit +.IR size ] +.in +8 +.RB [ \-p +.IR pfd ] +.RB [ \-rP ] +.RB { \-f [ \-\-show ]| \fIloopdev\fP } +.I file +.sp +.in -13 +Resize loop device: +.sp +.in +5 +.B "losetup \-c" +.I loopdev +.in -5 +.ad b +.SH DESCRIPTION +.B losetup +is used to associate loop devices with regular files or block devices, +to detach loop devices and to query the status of a loop device. If only the +\fIloopdev\fP argument is given, the status of the corresponding loop +device is shown. + +.SH OPTIONS ++The \fIsize\fR and \fIoffset\fR arguments may be followed by the multiplicative ++suffixes KiB=1024, MiB=1024*1024, and so on for GiB, TiB, PiB, EiB, ZiB and YiB ++(the "iB" is optional, e.g. "K" has the same meaning as "KiB") or the suffixes ++KB=1000, MB=1000*1000, and so on for GB, PB, EB, ZB and YB. + +.IP "\fB\-a, \-\-all\fP" +show status of all loop devices. Note that not all information are accessible +for non-root users. +.IP "\fB\-c, \-\-set-capacity\fP \fIloopdev\fP +force loop driver to reread size of the file associated with the specified loop device +.IP "\fB\-d, \-\-detach\fP \fIloopdev\fP..." +detach the file or device associated with the specified loop device(s) +.IP "\fB\-D, \-\-detach-all\fP" +detach all associated loop devices +.IP "\fB\-e, \-E, \-\-encryption \fIencryption_type\fP" +enable data encryption with specified name or number +.IP "\fB\-f, \-\-find\fP" +find the first unused loop device. If a +.I file +argument is present, use this device. Otherwise, print its name +.IP "\fB\-h, \-\-help\fP" +print help +.IP "\fB\-j, \-\-associated \fIfile\fP" +show status of all loop devices associated with given +.I file +.IP "\fB\-o, \-\-offset \fIoffset\fP" +the data start is moved \fIoffset\fP bytes into the specified file or +device +.IP "\fB\-\-sizelimit \fIsize\fP" +the data end is set to no more than \fIsize\fP bytes after the data start +.IP "\fB\-p, \-\-pass-fd \fInum\fP" +read the passphrase from file descriptor with number +.I num +instead of from the terminal +.IP "\fB\-P, \-\-partscan\fP" +force kernel to scan partition table on newly created loop device +.IP "\fB\-r, \-\-read-only\fP" +setup read-only loop device +.IP "\fB\-\-show\fP" +print device name if the +.I -f +option and a +.I file +argument are present. +.IP "\fB\-v, \-\-verbose\fP" +verbose mode + +.SH ENCRYPTION +.B Cryptoloop is deprecated in favor of dm-crypt. For more details see +.B cryptsetup (8). It is possible that all bug reports regarding to -E/-e +.B options will be ignored. + + +It is possible to specify transfer functions (for encryption/decryption +or other purposes) using one of the +.B \-E +and +.B \-e +options. +There are two mechanisms to specify the desired encryption: by number +and by name. If an encryption is specified by number then one +has to make sure that the Linux kernel knows about the encryption with that +number, probably by patching the kernel. Standard numbers that are +always present are 0 (no encryption) and 1 (XOR encryption). +When the cryptoloop module is loaded (or compiled in), it uses number 18. +This cryptoloop module will take the name of an arbitrary encryption type +and find the module that knows how to perform that encryption. + +.SH RETURN VALUE +.B losetup +returns 0 on success, nonzero on failure. When +.B losetup +displays the status of a loop device, it returns 1 if the device +is not configured and 2 if an error occurred which prevented +from determining the status of the device. + +.SH FILES +.TP +.I /dev/loop[0..N] +loop block devices +.TP +.I /dev/loop-cotrol +loop control device + +.SH EXAMPLE +The following commands can be used as an example of using the loop device. +.nf +.IP +# dd if=/dev/zero of=~/file.img bs=1MiB count=10 +# losetup --find --show ~/file.img +/dev/loop0 +# mkfs -t ext2 /dev/loop0 +# mount /dev/loop0 /mnt + ... +# umount /dev/loop0 +# losetup --detach /dev/loop0 +.fi +.SH AUTHORS +Karel Zak <kzak@redhat.com>, based on original version from +Theodore Ts'o <tytso@athena.mit.edu> +.SH AVAILABILITY +The losetup command is part of the util-linux package and is available from +ftp://ftp.kernel.org/pub/linux/utils/util-linux/. |