.\" Revision 1.0 93/06/3 23:00  chk
.\" Initial revision
.\"
.\"
.TH TUNE2FS 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
.SH NAME
tune2fs \- adjust tunable filesystem parameters on second extended filesystems
.SH SYNOPSIS
.B tune2fs
[
.B \-l
]
[
.B \-c
.I max-mount-counts
]
[
.B \-e
.I errors-behavior
]
[
.B \-i
.I interval-between-checks
]
[
.B \-m
.I reserved-blocks-percentage
]
[
.B \-r
.I reserved-blocks-count
]
[
.B \-s
.I sparse-super-flag
]
[
.B \-u
.I user
]
[
.B \-g
.I group
]
[
.B \-C
.I mount-count
]
[
.B \-L
.I volume-name
]
[
.B \-M
.I last-mounted-directory
]
[
.B \-O 
\fR[^]\fIfeature\fR[,...]
]
[
.B \-U
.I UUID
]
device
.SH DESCRIPTION
.BI tune2fs
adjusts tunable filesystem parameters on a Linux second extended filesystem.
.SH OPTIONS
.TP
.BI \-c " max-mount-counts"
adjust the maximal mounts count between two filesystem checks.
.TP
.BI \-e " error-behavior"
change the behavior of the kernel code when errors are detected.
.I error-behavior
can be one of the following:
.br
\	continue\	\	Continue normal execution.
.br
\	remount-ro\	Remount filesystem read-only.
.br
\	panic\	\	Cause a kernel panic.
.TP
.BI \-g " group"
set the user group which can benefit from the reserved blocks.
.br
.I group
can be a numerical gid or a group name.
.TP
.BI \-i " interval-between-checks\fR[\fBd\fR|\fBm\fR|\fBw\fR]"
adjust the maximal time between two filesystem checks. 
No postfix or
.B d
result in days,
.B m
in months, and
.B w
in weeks.  A value of zero will disable the timedependent checking.
.TP
.B \-l
list the contents of the filesystem superblock.
.TP
.BI \-m " reserved-blocks-percentage"
adjust the reserved blocks percentage on the given device.
.TP
.BI \-r " reserved-blocks-count"
adjust the reserved blocks count on the given device.
.TP
.BI \-s " sparse_super_flag"
set or reset the sparse_superblock flag.  The sparse_superblock feature
saves space on really big filesystems.
.B Warning:
The Linux 2.0 kernel does not properly support this feature.  Neither do
all Linux 2.1 kernels; please don't use this unless you know what you're
doing!
.TP
.BI \-u " user"
set the user who can benefit from the reserved blocks.
.I user
can be a numerical uid or a user name.
.TP
.BI \-C " mount-count"
set the number of times the filesystem has been mounted.
.TP
.BI \-L " volume-label"
set the volume label of the filesystem.  
Ext2 filesystem labels can be at most 16 characters long; if
.I volume-label 
is longer than 16 characters, 
.B tune2fs
will truncate it and print a warning message.  
.TP
.BI \-M " last-mounted-directory"
set the last-mounted directory for the filesystem.
.TP
.BI \-O " \fR[^]\fIfeature\fR[,...]"
set or clear the indicated filesystem features (options) in the filesystem.
.I Feature
can be one of the following supported filesystem options: 
.IR sparse ,
which cause the filesystem to use sparse superblocks, and
.IR filetype ,
which will cause the filesystem to store file type information in 
directory entries.  After setting or clearing either filesystem feature,
e2fsck must be run on the filesystem.
.TP
.BI \-U " UUID"
set the UUID of the filesystem.  A sample UUID looks like this: 
"c1b9d5a2-f162-11cf-9ece-0020afc76f16".  The uuid may also be
.IR null ,
which will set the filesystem UUID to the null UUID.  The uuid may also be
.IR random ,
which will generate a new random UUID for the filesystem.
.SH BUGS
We haven't found any bugs yet. Perhaps there are bugs but it's unlikely.
.SH WARNING
Never use tune2fs to change parameters of a read/write mounted filesystem!
.B Use this utility
.B at your own risk.
You're modifying a filesystem!
.SH AUTHOR
.B tune2fs 
was written by Remy Card <card@masi.ibp.fr>, the developer and maintainer
of the ext2 fs.
.B tune2fs
uses the ext2fs library written by Theodore Ts'o <tytso@mit.edu>.
This manual page was written by Christian Kuhtz <chk@data-hh.Hanse.DE>.
Timedependent checking was added by Uwe Ohse <uwe@tirka.gun.de>.
.SH AVAILABILITY
.B tune2fs
is part of the e2fsprogs package and is available for anonymous 
ftp from tsx-11.mit.edu in /pub/linux/packages/ext2fs.
.SH SEE ALSO
.BR dumpe2fs (8),
.BR e2fsck (8),
.BR mke2fs (8)