neulab/tldr huggingface dataset:
The lower filesystem can be any filesystem supported by Linux and does not need to be writable. The lower filesystem can even be another overlayfs. The upper filesystem will normally be writable and if it is it must support the creation of trusted.* extended attributes, and must provide a valid d_type in readdir responses, so NFS is not suitable.
A read-only overlay of two read-only filesystems may use any filesystem type. The options lowerdir and upperdir are combined into a merged directory by using:
mount -t overlay  overlay  \ -olowerdir=/lower,upperdir=/upper,workdir=/work  /merged
lowerdir=directory Any filesystem, does not need to be on a writable filesystem.
upperdir=directory The upperdir is normally on a writable filesystem.
workdir=directory The workdir needs to be an empty directory on the same filesystem as upperdir.
userxattr Use the "user.overlay." xattr namespace instead of "trusted.overlay.". This is useful for unprivileged mounting of overlayfs.
redirect_dir={on|off|follow|nofollow} If the redirect_dir feature is enabled, then the directory will be copied up (but not the contents). Then the "{trusted|user}.overlay.redirect" extended attribute is set to the path of the original location from the root of the overlay. Finally the directory is moved to the new location.
on Redirects are enabled.
off Redirects are not created and only followed if "redirect_always_follow" feature is enabled in the kernel/module config.
follow Redirects are not created, but followed.
nofollow Redirects are not created and not followed (equivalent to "redirect_dir=off" if "redirect_always_follow" feature is not enabled).
index={on|off} Inode index. If this feature is disabled and a file with multiple hard links is copied up, then this will "break" the link. Changes will not be propagated to other names referring to the same inode.
uuid={on|off} Can be used to replace UUID of the underlying filesystem in file handles with null, and effectively disable UUID checks. This can be useful in case the underlying disk is copied and the UUID of this copy is changed. This is only applicable if all lower/upper/work directories are on the same filesystem, otherwise it will fallback to normal behaviour.
nfs_export={on|off} When the underlying filesystems supports NFS export and the "nfs_export" feature is enabled, an overlay filesystem may be exported to NFS.
With the “nfs_export” feature, on copy_up of any lower object, an index entry is created under the index directory. The index entry name is the hexadecimal representation of the copy up origin file handle. For a non-directory object, the index entry is a hard link to the upper inode. For a directory object, the index entry has an extended attribute "{trusted|user}.overlay.upper" with an encoded file handle of the upper directory inode.
When encoding a file handle from an overlay filesystem object, the following rules apply
•   For a non-upper object, encode a lower file handle from lower inode
•   For an indexed object, encode a lower file handle from copy_up origin
•   For a pure-upper object and for an existing non-indexed upper object, encode an upper file handle from upper inode
The encoded overlay file handle includes
•   Header including path type information (e.g. lower/upper)
•   UUID of the underlying filesystem
•   Underlying filesystem encoding of underlying inode
This encoding format is identical to the encoding format file handles that are stored in extended attribute "{trusted|user}.overlay.origin". When decoding an overlay file handle, the following steps are followed
•   Find underlying layer by UUID and path type information.
•   Decode the underlying filesystem file handle to underlying dentry.
•   For a lower file handle, lookup the handle in index directory by name.
•   If a whiteout is found in index, return ESTALE. This represents an overlay object that was deleted after its file handle was encoded.
•   For a non-directory, instantiate a disconnected overlay dentry from the decoded underlying dentry, the path type and index inode, if found.
•   For a directory, use the connected underlying decoded dentry, path type and index, to lookup a connected overlay dentry.
Decoding a non-directory file handle may return a disconnected dentry. copy_up of that disconnected dentry will create an upper index entry with no upper alias.
When overlay filesystem has multiple lower layers, a middle layer directory may have a "redirect" to lower directory. Because middle layer "redirects" are not indexed, a lower file handle that was encoded from the "redirect" origin directory, cannot be used to find the middle or upper layer directory. Similarly, a lower file handle that was encoded from a descendant of the "redirect" origin directory, cannot be used to reconstruct a connected overlay path. To mitigate the cases of directories that cannot be decoded from a lower file handle, these directories are copied up on encode and encoded as an upper file handle. On an overlay filesystem with no upper layer this mitigation cannot be used NFS export in this setup requires turning off redirect follow (e.g. "redirect_dir=nofollow").
The overlay filesystem does not support non-directory connectable file handles, so exporting with the subtree_check exportfs configuration will cause failures to lookup files over NFS.
When the NFS export feature is enabled, all directory index entries are verified on mount time to check that upper file handles are not stale. This verification may cause significant overhead in some cases.
Note: the mount options index=off,nfs_export=on are conflicting for a read-write mount and will result in an error.
xinfo={on|off|auto} The "xino" feature composes a unique object identifier from the real object st_ino and an underlying fsid index. The "xino" feature uses the high inode number bits for fsid, because the underlying filesystems rarely use the high inode number bits. In case the underlying inode number does overflow into the high xino bits, overlay filesystem will fall back to the non xino behavior for that inode.
For a detailed description of the effect of this option please refer to https://www.kernel.org/doc/html/latest/filesystems/overlayfs.html?highlight=overlayfs
metacopy={on|off} When metadata only copy up feature is enabled, overlayfs will only copy up metadata (as opposed to whole file), when a metadata specific operation like chown/chmod is performed. Full file will be copied up later when file is opened for WRITE operation.
In other words, this is delayed data copy up operation and data is copied up when there is a need to actually modify data.
volatile Volatile mounts are not guaranteed to survive a crash. It is strongly recommended that volatile mounts are only used if data written to the overlay can be recreated without significant effort.
The advantage of mounting with the "volatile" option is that all forms of sync calls to the upper filesystem are omitted.
In order to avoid a giving a false sense of safety, the syncfs (and fsync) semantics of volatile mounts are slightly different than that of the rest of VFS. If any writeback error occurs on the upperdir’s filesystem after a volatile mount takes place, all sync functions will return an error. Once this condition is reached, the filesystem will not recover, and every subsequent sync call will return an error, even if the upperdir has not experience a new error since the last sync call.
When overlay is mounted with "volatile" option, the directory "$workdir/work/incompat/volatile" is created. During next mount, overlay checks for this directory and refuses to mount if present. This is a strong indicator that user should throw away upper and work directories and create fresh one. In very limited cases where the user knows that the system has not crashed and contents of upperdir are intact, The "volatile" directory can be removed.
Mount options for reiserfs Reiserfs is a journaling filesystem.
conv Instructs version 3.6 reiserfs software to mount a version 3.5 filesystem, using the 3.6 format for newly created objects. This filesystem will no longer be compatible with reiserfs 3.5 tools.
hash={rupasov|tea|r5|detect} Choose which hash function reiserfs will use to find files within directories.
rupasov A hash invented by Yury Yu. Rupasov. It is fast and preserves locality, mapping lexicographically close file names to close hash values. This option should not be used, as it causes a high probability of hash collisions.
tea A Davis-Meyer function implemented by Jeremy Fitzhardinge. It uses hash permuting bits in the name. It gets high randomness and, therefore, low probability of hash collisions at some CPU cost. This may be used if EHASHCOLLISION errors are experienced with the r5 hash.
r5 A modified version of the rupasov hash. It is used by default and is the best choice unless the filesystem has huge directories and unusual file-name patterns.
detect Instructs mount to detect which hash function is in use by examining the filesystem being mounted, and to write this information into the reiserfs superblock. This is only useful on the first mount of an old format filesystem.
hashed_relocation Tunes the block allocator. This may provide performance improvements in some situations.
no_unhashed_relocation Tunes the block allocator. This may provide performance improvements in some situations.
noborder Disable the border allocator algorithm invented by Yury Yu. Rupasov. This may provide performance improvements in some situations.
nolog Disable journaling. This will provide slight performance improvements in some situations at the cost of losing reiserfs’s fast recovery from crashes. Even with this option turned on, reiserfs still performs all journaling operations, save for actual writes into its journaling area. Implementation of nolog is a work in progress.
notail By default, reiserfs stores small files and 'file tails' directly into its tree. This confuses some utilities such as lilo(8). This option is used to disable packing of files into the tree.
replayonly Replay the transactions which are in the journal, but do not actually mount the filesystem. Mainly used by reiserfsck.
resize=number A remount option which permits online expansion of reiserfs partitions. Instructs reiserfs to assume that the device has number blocks. This option is designed for use with devices which are under logical volume management (LVM). There is a special resizer utility which can be obtained from ftp://ftp.namesys.com/pub/reiserfsprogs.
user_xattr Enable Extended User Attributes. See the attr(1) manual page.
acl Enable POSIX Access Control Lists. See the acl(5) manual page.
barrier=none / barrier=flush This disables / enables the use of write barriers in the journaling code. barrier=none disables, barrier=flush enables (default). This also requires an IO stack which can support barriers, and if reiserfs gets an error on a barrier write, it will disable barriers again with a warning. Write barriers enforce proper on-disk ordering of journal commits, making volatile disk write caches safe to use, at some performance penalty. If your disks are battery-backed in one way or another, disabling barriers may safely improve performance.
Mount options for ubifs UBIFS is a flash filesystem which works on top of UBI volumes. Note that atime is not supported and is always turned off.
The device name may be specified as
ubiX_Y UBI device number X, volume number Y
ubiY UBI device number 0, volume number Y
ubiX:NAME UBI device number X, volume with name NAME
ubi:NAME UBI device number 0, volume with name NAME
Alternative ! separator may be used instead of :.
The following mount options are available:
bulk_read Enable bulk-read. VFS read-ahead is disabled because it slows down the filesystem. Bulk-Read is an internal optimization. Some flashes may read faster if the data are read at one go, rather than at several read requests. For example, OneNAND can do "read-while-load" if it reads more than one NAND page.
no_bulk_read Do not bulk-read. This is the default.
chk_data_crc Check data CRC-32 checksums. This is the default.
no_chk_data_crc Do not check data CRC-32 checksums. With this option, the filesystem does not check CRC-32 checksum for data, but it does check it for the internal indexing information. This option only affects reading, not writing. CRC-32 is always calculated when writing the data.
compr={none|lzo|zlib} Select the default compressor which is used when new files are written. It is still possible to read compressed files if mounted with the none option.
Mount options for udf UDF is the "Universal Disk Format" filesystem defined by OSTA, the Optical Storage Technology Association, and is often used for DVD-ROM, frequently in the form of a hybrid UDF/ISO-9660 filesystem. It is, however, perfectly usable by itself on disk drives, flash drives and other block devices. See also iso9660.
uid= Make all files in the filesystem belong to the given user. uid=forget can be specified independently of (or usually in addition to) uid=<user> and results in UDF not storing uids to the media. In fact the recorded uid is the 32-bit overflow uid -1 as defined by the UDF standard. The value is given as either <user> which is a valid user name or the corresponding decimal user id, or the special string "forget".
gid= Make all files in the filesystem belong to the given group. gid=forget can be specified independently of (or usually in addition to) gid=<group> and results in UDF not storing gids to the media. In fact the recorded gid is the 32-bit overflow gid -1 as defined by the UDF standard. The value is given as either <group> which is a valid group name or the corresponding decimal group id, or the special string "forget".
umask= Mask out the given permissions from all inodes read from the filesystem. The value is given in octal.
mode= If mode= is set the permissions of all non-directory inodes read from the filesystem will be set to the given mode. The value is given in octal.
dmode= If dmode= is set the permissions of all directory inodes read from the filesystem will be set to the given dmode. The value is given in octal.
bs= Set the block size. Default value prior to kernel version 2.6.30 was 2048. Since 2.6.30 and prior to 4.11 it was logical device block size with fallback to 2048. Since 4.11 it is logical block size with fallback to any valid block size between logical device block size and 4096.
For other details see the mkudffs(8) 2.0+ manpage, sections COMPATIBILITY and BLOCK SIZE.
unhide Show otherwise hidden files.
undelete Show deleted files in lists.
adinicb Embed data in the inode. (default)
noadinicb Don’t embed data in the inode.
shortad Use short UDF address descriptors.
longad Use long UDF address descriptors. (default)
nostrict Unset strict conformance.
iocharset= Set the NLS character set. This requires kernel compiled with CONFIG_UDF_NLS option.
utf8 Set the UTF-8 character set.
Mount options for debugging and disaster recovery novrs Ignore the Volume Recognition Sequence and attempt to mount anyway.
session= Select the session number for multi-session recorded optical media. (default= last session)
anchor= Override standard anchor location. (default= 256)
lastblock= Set the last block of the filesystem.
Unused historical mount options that may be encountered and should be removed uid=ignore Ignored, use uid=<user> instead.
gid=ignore Ignored, use gid=<group> instead.
volume= Unimplemented and ignored.
partition= Unimplemented and ignored.
fileset= Unimplemented and ignored.
rootdir= Unimplemented and ignored.
Mount options for ufs ufstype=value UFS is a filesystem widely used in different operating systems. The problem are differences among implementations. Features of some implementations are undocumented, so its hard to recognize the type of ufs automatically. That’s why the user must specify the type of ufs by mount option. Possible values are:
old Old format of ufs, this is the default, read only. (Don’t forget to give the -r option.)
44bsd For filesystems created by a BSD-like system (NetBSD, FreeBSD, OpenBSD).
ufs2 Used in FreeBSD 5.x supported as read-write.
5xbsd Synonym for ufs2.
sun For filesystems created by SunOS or Solaris on Sparc.
sunx86 For filesystems created by Solaris on x86.
hp For filesystems created by HP-UX, read-only.
nextstep For filesystems created by NeXTStep (on NeXT station) (currently read only).
nextstep-cd For NextStep CDROMs (block_size == 2048), read-only.
openstep For filesystems created by OpenStep (currently read only). The same filesystem type is also used by Mac OS X.
onerror=value Set behavior on error:
panic If an error is encountered, cause a kernel panic.
[lock|umount|repair] These mount options don’t do anything at present; when an error is encountered only a console message is printed.
Mount options for umsdos See mount options for msdos. The dotsOK option is explicitly killed by umsdos.
Mount options for vfat First of all, the mount options for fat are recognized. The dotsOK option is explicitly killed by vfat. Furthermore, there are
uni_xlate Translate unhandled Unicode characters to special escaped sequences. This lets you backup and restore filenames that are created with any Unicode characters. Without this option, a '?' is used when no translation is possible. The escape character is ':' because it is otherwise invalid on the vfat filesystem. The escape sequence that gets used, where u is the Unicode character, is: ':', (u & 0x3f), ((u>>6) & 0x3f), (u>>12).
posix Allow two files with names that only differ in case. This option is obsolete.
nonumtail First try to make a short name without sequence number, before trying name~num.ext.
utf8 UTF8 is the filesystem safe 8-bit encoding of Unicode that is used by the console. It can be enabled for the filesystem with this option or disabled with utf8=0, utf8=no or utf8=false. If uni_xlate gets set, UTF8 gets disabled.
shortname=mode Defines the behavior for creation and display of filenames which fit into 8.3 characters. If a long name for a file exists, it will always be the preferred one for display. There are four modes:
lower Force the short name to lower case upon display; store a long name when the short name is not all upper case.
win95 Force the short name to upper case upon display; store a long name when the short name is not all upper case.
winnt Display the short name as is; store a long name when the short name is not all lower case or all upper case.
mixed Display the short name as is; store a long name when the short name is not all upper case. This mode is the default since Linux 2.6.32.
Mount options for usbfs devuid=uid and devgid=gid and devmode=mode Set the owner and group and mode of the device files in the usbfs filesystem (default: uid=gid=0, mode=0644). The mode is given in octal.
busuid=uid and busgid=gid and busmode=mode Set the owner and group and mode of the bus directories in the usbfs filesystem (default: uid=gid=0, mode=0555). The mode is given in octal.
listuid=uid and listgid=gid and listmode=mode Set the owner and group and mode of the file devices (default: uid=gid=0, mode=0444). The mode is given in octal.
DM-VERITY SUPPORT (EXPERIMENTAL) The device-mapper verity target provides read-only transparent integrity checking of block devices using kernel crypto API. The mount command can open the dm-verity device and do the integrity verification before on the device filesystem is mounted. Requires libcryptsetup with in libmount (optionally via dlopen(3)). If libcryptsetup supports extracting the root hash of an already mounted device, existing devices will be automatically reused in case of a match. Mount options for dm-verity:
verity.hashdevice=path Path to the hash tree device associated with the source volume to pass to dm-verity.
verity.roothash=hex Hex-encoded hash of the root of verity.hashdevice. Mutually exclusive with verity.roothashfile.
verity.roothashfile=path Path to file containing the hex-encoded hash of the root of verity.hashdevice. Mutually exclusive with verity.roothash.
verity.hashoffset=offset If the hash tree device is embedded in the source volume, offset (default: 0) is used by dm-verity to get to the tree.
verity.fecdevice=path Path to the Forward Error Correction (FEC) device associated with the source volume to pass to dm-verity. Optional. Requires kernel built with CONFIG_DM_VERITY_FEC.
verity.fecoffset=offset If the FEC device is embedded in the source volume, offset (default: 0) is used by dm-verity to get to the FEC area. Optional.
verity.fecroots=value Parity bytes for FEC (default: 2). Optional.
verity.roothashsig=path Path to pkcs7(1ssl) signature of root hash hex string. Requires crypt_activate_by_signed_key() from cryptsetup and kernel built with CONFIG_DM_VERITY_VERIFY_ROOTHASH_SIG. For device reuse, signatures have to be either used by all mounts of a device or by none. Optional.
Supported since util-linux v2.35.
For example commands:
mksquashfs /etc /tmp/etc.squashfs dd if=/dev/zero of=/tmp/etc.hash bs=1M count=10 veritysetup format /tmp/etc.squashfs /tmp/etc.hash openssl smime -sign -in <hash> -nocerts -inkey private.key \ -signer private.crt -noattr -binary -outform der -out /tmp/etc.roothash.p7s mount -o verity.hashdevice=/tmp/etc.hash,verity.roothash=<hash>,\ verity.roothashsig=/tmp/etc.roothash.p7s /tmp/etc.squashfs /mnt
create squashfs image from /etc directory, verity hash device and mount verified filesystem image to /mnt. The kernel will verify that the root hash is signed by a key from the kernel keyring if roothashsig is used.
LOOP-DEVICE SUPPORT One further possible type is a mount via the loop device. For example, the command
mount /tmp/disk.img /mnt -t vfat -o loop=/dev/loop3
will set up the loop device /dev/loop3 to correspond to the file /tmp/disk.img, and then mount this device on /mnt.
If no explicit loop device is mentioned (but just an option '-o loop' is given), then mount will try to find some unused loop device and use that, for example
mount /tmp/disk.img /mnt -o loop
The mount command automatically creates a loop device from a regular file if a filesystem type is not specified or the filesystem is known for libblkid, for example:
mount /tmp/disk.img /mnt
mount -t ext4 /tmp/disk.img /mnt
This type of mount knows about three options, namely loop, offset and sizelimit, that are really options to losetup(8). (These options can be used in addition to those specific to the filesystem type.)
Since Linux 2.6.25 auto-destruction of loop devices is supported, meaning that any loop device allocated by mount will be freed by umount independently of /etc/mtab.
You can also free a loop device by hand, using losetup -d or umount -d.
Since util-linux v2.29, mount re-uses the loop device rather than initializing a new device if the same backing file is already used for some loop device with the same offset and sizelimit. This is necessary to avoid a filesystem corruption.
mount has the following exit status values (the bits can be ORed):
1 incorrect invocation or permissions
2 system error (out of memory, cannot fork, no more loop devices)
4 internal mount bug
8 user interrupt
16 problems writing or locking /etc/mtab
32 mount failure
64 some mount succeeded
The command mount -a returns 0 (all succeeded), 32 (all failed), or 64 (some failed, some succeeded).
The syntax of external mount helpers is:
/sbin/mount.suffix spec dir [-sfnv] [-N namespace] [-o options] [-t type.subtype]
where the suffix is the filesystem type and the -sfnvoN options have the same meaning as the normal mount options. The -t option is used for filesystems with subtypes support (for example /sbin/mount.fuse -t fuse.sshfs).
The command mount does not pass the mount options unbindable, runbindable, private, rprivate, slave, rslave, shared, rshared, auto, noauto, comment, x-*, loop, offset and sizelimit to the mount.<suffix> helpers. All other options are used in a comma-separated list as an argument to the -o option.
LIBBLKID_DEBUG=all enables libblkid debug output
LOOPDEV_DEBUG=all enables loop device setup debug output
See also "The files /etc/fstab, /etc/mtab and /proc/mounts" section above.
/etc/fstab filesystem table
/run/mount libmount private runtime directory
/etc/mtab table of mounted filesystems or symlink to /proc/mounts
/etc/mtab~ lock file (unused on systems with mtab symlink)
/etc/mtab.tmp temporary file (unused on systems with mtab symlink)
/etc/filesystems a list of filesystem types to try
A mount command existed in Version 5 AT&T UNIX.
It is possible for a corrupted filesystem to cause a crash.
Some Linux filesystems don’t support -o sync and -o dirsync (the ext2, ext3, ext4, fat and vfat filesystems do support synchronous updates (a la BSD) when mounted with the sync option).
The -o remount may not be able to change mount parameters (all ext2fs-specific parameters, except sb, are changeable with a remount, for example, but you can’t change gid or umask for the fatfs).
It is possible that the files /etc/mtab and /proc/mounts don’t match on systems with a regular mtab file. The first file is based only on the mount command options, but the content of the second file also depends on the kernel and others settings (e.g. on a remote NFS server — in certain cases the mount command may report unreliable information about an NFS mount point and the /proc/mount file usually contains more reliable information.) This is another reason to replace the mtab file with a symlink to the /proc/mounts file.
Checking files on NFS filesystems referenced by file descriptors (i.e. the fcntl and ioctl families of functions) may lead to inconsistent results due to the lack of a consistency check in the kernel even if the noac mount option is used.
The loop option with the offset or sizelimit options used may fail when using older kernels if the mount command can’t confirm that the size of the block device has been configured as requested. This situation can be worked around by using the losetup(8) command manually before calling mount with the configured loop device.
Karel Zak <kzak@redhat.com>
mount(2), umount(2), filesystems(5), fstab(5), nfs(5), xfs(5), mount_namespaces(7), xattr(7), e2label(8), findmnt(8), losetup(8), lsblk(8), mke2fs(8), mountd(8), nfsd(8), swapon(8), tune2fs(8), umount(8), xfs_admin(8)
The mount command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.
VGCHANGE(8)                  System Manager's Manual                 VGCHANGE(8)
vgchange — Change volume group attributes
vgchange option_args position_args [ option_args ] [ position_args ]
-a|--activate y|n|ay --activationmode partial|degraded|complete --addtag Tag --alloc contiguous|cling|cling_by_tags|normal|anywhere|inherit -A|--autobackup y|n --commandprofile String --config String -d|--debug --deltag Tag --detachprofile --devices PV --devicesfile String --driverloaded y|n -f|--force -h|--help -K|--ignoreactivationskip --ignorelockingfailure --ignoremonitoring --journal String --lockopt String --lockstart --lockstop --locktype sanlock|dlm|none -l|--logicalvolume Number --longhelp -p|--maxphysicalvolumes Number --metadataprofile String --monitor y|n --nohints --nolocking --noudevsync -P|--partial -s|--physicalextentsize Size[m|UNIT] --poll y|n --profile String --pvmetadatacopies 0|1|2 -q|--quiet --readonly --refresh --reportformat basic|json -x|--resizeable y|n -S|--select String --setautoactivation y|n --sysinit --systemid String -t|--test -u|--uuid -v|--verbose --version --[vg]metadatacopies all|unmanaged|Number -y|--yes
vgchange changes VG attributes, changes LV activation in the kernel, and includes other utilities for VG maintenance.
Change a general VG attribute. For options listed in parentheses, any one is required, after which the others are optional.
vgchange ( -l|--logicalvolume Number -p|--maxphysicalvolumes Number -u|--uuid -s|--physicalextentsize Size[m|UNIT] -x|--resizeable y|n --addtag Tag --deltag Tag --alloc contiguous|cling|cling_by_tags|normal|anywhere|inherit --pvmetadatacopies 0|1|2 --[vg]metadatacopies all|unmanaged|Number --profile String --detachprofile --metadataprofile String --setautoactivation y|n ) [ -A|--autobackup y|n ] [ -S|--select String ] [ -f|--force ] [    --poll y|n ] [    --ignoremonitoring ] [    --noudevsync ] [    --reportformat basic|json ] [ COMMON_OPTIONS ] [ VG|Tag|Select ... ]
Start or stop monitoring LVs from dmeventd.
vgchange --monitor y|n [ -A|--autobackup y|n ] [ -S|--select String ] [ -f|--force ] [    --sysinit ] [    --ignorelockingfailure ] [    --poll y|n ] [    --ignoremonitoring ] [    --noudevsync ] [    --reportformat basic|json ] [ COMMON_OPTIONS ] [ VG|Tag|Select ... ]
Start or stop processing LV conversions.
vgchange --poll y|n [ -A|--autobackup y|n ] [ -S|--select String ] [ -f|--force ] [    --ignorelockingfailure ] [    --ignoremonitoring ] [    --noudevsync ] [    --reportformat basic|json ] [ COMMON_OPTIONS ] [ VG|Tag|Select ... ]
Activate or deactivate LVs.
vgchange -a|--activate y|n|ay [ -K|--ignoreactivationskip ] [ -P|--partial ] [ -A|--autobackup y|n ] [ -S|--select String ] [ -f|--force ] [    --activationmode partial|degraded|complete ] [    --sysinit ] [    --readonly ] [    --ignorelockingfailure ] [    --monitor y|n ] [    --poll y|n ] [    --ignoremonitoring ] [    --noudevsync ] [    --reportformat basic|json ] [ COMMON_OPTIONS ] [ VG|Tag|Select ... ]
Reactivate LVs using the latest metadata.
vgchange --refresh [ -A|--autobackup y|n ] [ -S|--select String ] [ -f|--force ] [    --sysinit ] [    --ignorelockingfailure ] [    --poll y|n ] [    --ignoremonitoring ] [    --noudevsync ] [    --reportformat basic|json ] [ COMMON_OPTIONS ] [ VG|Tag|Select ... ]
Change the system ID of a VG.
vgchange --systemid String VG [ COMMON_OPTIONS ]
Start the lockspace of a shared VG in lvmlockd.
vgchange --lockstart [ -S|--select String ] [ COMMON_OPTIONS ] [ VG|Tag|Select ... ]
Stop the lockspace of a shared VG in lvmlockd.
vgchange --lockstop [ -S|--select String ] [ COMMON_OPTIONS ] [ VG|Tag|Select ... ]
Change the lock type for a shared VG.
vgchange --locktype sanlock|dlm|none VG [ COMMON_OPTIONS ]
-a|--activate y|n|ay Change the active state of LVs.  An active LV can be used through a block device, allowing data on the LV to be accessed.  y makes LVs active, or available.  n makes LVs inactive, or unavailable. The block device for the LV is added or removed from the system using device-mapper in the kernel.  A symbolic link /dev/VGName/LVName pointing to the device node is also added/removed.  All software and scripts should access the device through the symbolic link and present this as the name of the device.  The location and name of the underlying device node may depend on the distribution, configuration (e.g. udev), or release version.  ay specifies autoactivation, which is used by system- generated activation commands.  By default, LVs are autoactivated. An autoactivation property can be set on a VG or LV to disable autoactivation, see --setautoactivation y|n in vgchange, lvchange, vgcreate, and lvcreate.  Display the property with vgs or lvs "-o autoactivation".  The lvm.conf(5) auto_activation_volume_list includes names of VGs or LVs that should be autoactivated, and anything not listed is not autoactivated.  When auto_activation_volume_list is undefined (the default), it has no effect.  If auto_activation_volume_list is defined and empty, no LVs are autoactivated.  Items included by auto_activation_volume_list will not be autoactivated if the autoactivation property has been disabled.  See lvmlockd(8) for more information about activation options ey and sy for shared VGs.
--activationmode partial|degraded|complete Determines if LV activation is allowed when PVs are missing, e.g. because of a device failure.  complete only allows LVs with no missing PVs to be activated, and is the most restrictive mode. degraded allows RAID LVs with missing PVs to be activated.  (This does not include the "mirror" type, see "raid1" instead.)  partial allows any LV with missing PVs to be activated, and should only be used for recovery or repair.  For default, see lvm.conf(5) activation_mode.  See lvmraid(7) for more information.
--deltag Tag Deletes a tag from a PV, VG or LV. This option can be repeated to delete multiple tags at once. See lvm(8) for information about tags.
--detachprofile Detaches a metadata profile from a VG or LV.  See lvm.conf(5) for more information about profiles.
-K|--ignoreactivationskip Ignore the "activation skip" LV flag during activation to allow LVs with the flag set to be activated.
--ignoremonitoring Do not interact with dmeventd unless --monitor is specified.  Do not use this if dmeventd is already monitoring a device.
--lockstart Start the lockspace of a shared VG in lvmlockd.  lvmlockd locks becomes available for the VG, allowing LVM to use the VG.  See lvmlockd(8) for more information.
--lockstop Stop the lockspace of a shared VG in lvmlockd.  lvmlockd locks become unavailable for the VG, preventing LVM from using the VG. See lvmlockd(8) for more information.
--locktype sanlock|dlm|none Change the VG lock type to or from a shared lock type used with lvmlockd.  See lvmlockd(8) for more information.
-l|--logicalvolume Number Sets the maximum number of LVs allowed in a VG.
--monitor y|n Start (yes) or stop (no) monitoring an LV with dmeventd.  dmeventd monitors kernel events for an LV, and performs automated maintenance for the LV in reponse to specific events.  See dmeventd(8) for more information.
-P|--partial Commands will do their best to activate LVs with missing PV extents.  Missing extents may be replaced with error or zero segments according to the  missing_stripe_filler setting. Metadata may not be changed with this option.
-s|--physicalextentsize Size[m|UNIT] Sets the physical extent size of PVs in the VG.  The value must be either a power of 2 of at least 1 sector (where the sector size is the largest sector size of the PVs currently used in the VG), or at least 128KiB.  Once this value has been set, it is difficult to change without recreating the VG, unless no extents need moving. Before increasing the physical extent size, you might need to use lvresize, pvresize and/or pvmove so that everything fits. For example, every contiguous range of extents used in a LV must start and end on an extent boundary.
--poll y|n When yes, start the background transformation of an LV.  An incomplete transformation, e.g. pvmove or lvconvert interrupted by reboot or crash, can be restarted from the last checkpoint with --poll y.  When no, background transformation of an LV will not occur, and the transformation will not complete. It may not be appropriate to immediately poll an LV after activation, in which case --poll n can be used to defer polling until a later --poll y command.
--refresh If the LV is active, reload its metadata.  This is not necessary in normal operation, but may be useful if something has gone wrong, or if some form of manual LV sharing is being used.
-x|--resizeable y|n Enables or disables the addition or removal of PVs to/from a VG (by vgextend/vgreduce).
--sysinit Indicates that vgchange/lvchange is being invoked from early system initialisation scripts (e.g. rc.sysinit or an initrd), before writable filesystems are available. As such, some functionality needs to be disabled and this option acts as a shortcut which selects an appropriate set of options. Currently, this is equivalent to using --ignorelockingfailure, --ignoremonitoring, --poll n, and setting env var LVM_SUPPRESS_LOCKING_FAILURE_MESSAGES.  vgchange/lvchange skip autoactivation, and defer to pvscan autoactivation.
--systemid String Changes the system ID of the VG.  Using this option requires caution because the VG may become foreign to the host running the command, leaving the host unable to access it.  See lvmsystemid(7) for more information.
-u|--uuid Generate new random UUID for specified VGs.
Select Select indicates that a required positional parameter can be omitted if the --select option is used.  No arg appears in this position.
If vgchange recognizes COW snapshot LVs that were dropped because they ran out of space, it displays a message informing the administrator that the snapshots should be removed.
Activate all LVs in all VGs on all existing devices. vgchange -a y
Change the maximum number of LVs for an inactive VG. vgchange -l 128 vg00
GIT-SHOW-TREE(1)                   Git Extras                   GIT-SHOW-TREE(1)
git-show-tree - show branch tree of commit history
git-show-tree
Show the decorated graph view of one liner summarized commits from all branches.
Output the commit history log for all branches as tree view:
*   4b57684 (HEAD, develop) Merge branch upstream master. |\ | *   515e94a Merge pull request #128 from nickl-/git-extras-html-hyperlinks | |\ | | * 815db8b (nickl/git-extras-html-hyperlinks, git-extras-html-hyperlinks) help ronn make hyperlinks. | * | 7398d10 (nickl/develop) Fix #127 git-ignore won´t add duplicates. | |/ | | * ab72c1e (refs/stash) WIP on develop: 5e943f5 Fix #127 git-ignore won´t add duplicates. | |/ |/| * | 730ca89 (bolshakov) Rebase bolshakov with master |/ * 60f8371 (origin/master, origin/HEAD, master) Merge pull request #126 from agrimaldi/fix-changelog-last-tag * 9627780 (tag: 1.7.0) Release 1.7.0 * 2e53ff6 (tag: 1.6.0) Release 1.6.0 * bbd32d8 (tag: 1.5.1) Release 1.5.1 | * 6b6b758 (nickl/gh-pages, gh-pages) add example git-extras to gh-pages | * 19cfd11 (origin/gh-pages) Index page | | * 881a70e (tag: 1.5.0) Release 1.5.0 | |/ |/| * | 4db5ee0 (tag: 1.4.0) Release 1.4.0 * | 9b0bc89 (tag: 1.3.0) Release 1.3.0 * | be49961 (tag: 1.2.0) Release 1.2.0 * | c1d2dfc (tag: 1.1.0) Release 1.1.0 * | 4a56adb (tag: 1.0.0) Release 1.0.0 * | 948308b (tag: 0.9.0) Release 0.9.0 * | 40b131d (tag: 0.8.1) Release 0.8.1 * | 391431d (tag: 0.8.0) Release 0.8.0
Written by Nick Lombard github@jigsoft.co.za
GNOME-EXTENSIONS(1)               User Commands              GNOME-EXTENSIONS(1)
gnome-extensions - Command line tool for managing GNOME extensions
gnome-extensions help [COMMAND]
gnome-extensions version
gnome-extensions enable UUID
gnome-extensions disable UUID
gnome-extensions reset UUID
gnome-extensions info UUID
gnome-extensions show UUID
gnome-extensions list [OPTION...]
gnome-extensions prefs UUID
gnome-extensions create [OPTION...]
gnome-extensions pack [OPTION...]
gnome-extensions install [OPTION...] PACK
gnome-extensions uninstall UUID
gnome-extensions is a utility that makes some common GNOME extensions operations available on the command line.
All commands except for help and version handle the following options:
--quiet, -q Do not print error messages
help [COMMAND] Displays a short synopsis of the available commands or provides detailed help on a specific command.
version Prints the program version.
enable UUID Enables the extension identified by UUID.
The command will not detect any errors from the extension itself, use the info command to confirm that the extension state is ENABLED.
If the extension is already enabled, the command will do nothing.
disable UUID Disables the extension identified by UUID.
If the extension is not enabled, the command will do nothing.
reset UUID Reset the extension identified by UUID.
The extension will be disabled in GNOME, but may be enabled by other sessions like GNOME Classic.
info UUID Show details of the extension identified by UUID, including name, description and state.
show UUID Synonym of info.
list [OPTION...] Displays a list of installed extensions.
Options --user Include extensions installed in the user’s $HOME
--system Include extensions installed in the system
--enabled Include enabled extensions
--disabled Include disabled extensions
--prefs Only include extensions with preferences
--updates Only include extensions with pending updates
-d, --details Show some extra information for each extension
prefs UUID Open the preference dialog of the extension identified by UUID.
create [OPTION...] Creates a new extension from a template.
Options --name=NAME Set the user-visible name in the extension’s metadata to NAME
--description=DESC Set the description in the extension’s metadata to DESC
--uuid=UUID Set the unique extension ID in the metadata to UUID
--template=TEMPLATE Use TEMPLATE as base for the new extension
-i, --interactive Prompt for any extension metadata that hasn’t been provided on the command line
pack [OPTION...] [SOURCE-DIRECTORY] Creates an extension bundle that is suitable for publishing.
The bundle will always include the required files extension.js and metadata.json, as well as the optional stylesheet.css and prefs.js if found. Each additional source that should be included must be specified with --extra-source.
If the extension includes one or more GSettings schemas, they can either be placed in a schemas/ folder to be picked up automatically, or be specified with --schema.
Similarily, translations are included automatically when they are located in a po/ folder, otherwise the --podir option can be used to point to the correct directory. If no gettext domain is provided on the command line, the value of the gettext-domain metadata field is used if it exists, and the extension UUID if not.
All files are searched in SOURCE-DIRECTORY if specified, or the current directory otherwise.
Options --extra-source=FILE Additional source to include in the bundle
--schema=SCHEMA A GSettings schema that should be compiled and included
--podir=PODIR A directory with translations that should be compiled and included
--gettext-domain=DOMAIN The gettext domain to use for translations
-f, --force Overwrite an existing pack
-o, --out-dir=DIRECTORY The directory where the pack should be created
install [OPTION...] PACK Installs an extension from the bundle PACK.
The command unpacks the extension files and moves them to the expected location in the user’s $HOME, so that it will be loaded in the next session.
It is mainly intended for testing, not as a replacement for the extension website. As extensions have privileged access to the user’s session, it is advised to never load extensions from untrusted sources without carefully reviewing their content.
Options --force Override an existing extension
uninstall UUID Uninstalls the extension identified by UUID.
On success 0 is returned, a non-zero failure code otherwise.
The tool is part of the gnome-shell project, and bugs should be reported in its issue tracker at https://gitlab.gnome.org/GNOME/gnome-shell/issues.
CERTBOT(7)                           Certbot                          CERTBOT(7)
certbot - Certbot Documentation
NOTE: To get started quickly, use the interactive installation guide.
Certbot is part of EFF’s effort to encrypt the entire Internet. Secure communication over the Web relies on HTTPS, which requires the use of a digital certificate that lets browsers verify the identity of web servers (e.g., is that really google.com?). Web servers obtain their certificates from trusted third parties called certificate authorities (CAs). Certbot is an easy-to-use client that fetches a certificate from Let’s Encrypt—an open certificate authority launched by the EFF, Mozilla, and others—and deploys it to a web server.
Anyone who has gone through the trouble of setting up a secure website knows what a hassle getting and maintaining a certificate is. Certbot and Let’s Encrypt can automate away the pain and let you turn on and manage HTTPS with simple commands. Using Certbot and Let's Encrypt is free, so there’s no need to arrange payment.
How you use Certbot depends on the configuration of your web server. The best way to get started is to use our interactive guide. It generates instructions based on your configuration settings. In most cases, you’ll need root or administrator access to your web server to run Certbot.
Certbot is meant to be run directly on your web server, not on your personal computer. If you’re using a hosted service and don’t have direct access to your web server, you might not be able to use Certbot. Check with your hosting provider for documentation about uploading certificates or using certificates issued by Let’s Encrypt.
Certbot is a fully-featured, extensible client for the Let's Encrypt CA (or any other CA that speaks the ACME protocol) that can automate the tasks of obtaining certificates and configuring webservers to use them. This client runs on Unix-based operating systems.
To see the changes made to Certbot between versions please refer to our changelog.
Until May 2016, Certbot was named simply letsencrypt or letsencrypt-auto, depending on install method. Instructions on the Internet, and some pieces of the software, may still refer to this older name.
Contributing If you'd like to contribute to this project please read Developer Guide.
This project is governed by EFF's Public Projects Code of Conduct.
How to run the client The easiest way to install and run Certbot is by visiting certbot.eff.org, where you can find the correct instructions for many web server and OS combinations.  For more information, see Get Certbot.
Understanding the client in more depth To understand what the client is doing in detail, it's important to understand the way it uses plugins.  Please see the explanation of plugins in the User Guide.
Links Documentation: https://certbot.eff.org/docs
Software project: https://github.com/certbot/certbot
Notes for developers: https://certbot.eff.org/docs/contributing.html
Main Website: https://certbot.eff.org
Let's Encrypt Website: https://letsencrypt.org
Community: https://community.letsencrypt.org
ACME spec: RFC 8555
ACME working area in github (archived): https://github.com/ietf-wg-acme/acme
Azure Pipelines CI status
System Requirements See https://certbot.eff.org/docs/install.html#system-requirements.
WHAT IS A CERTIFICATE? A public key or digital certificate (formerly called an SSL certificate) uses a public key and a private key to enable secure communication between a client program (web browser, email client, etc.) and a server over an encrypted SSL (secure socket layer) or TLS (transport layer security) connection.  The certificate is used both to encrypt the initial stage of communication (secure key exchange) and to identify the server. The certificate includes information about the key, information about the server identity, and the digital signature of the certificate issuer. If the issuer is trusted by the software that initiates the communication, and the signature is valid, then the key can be used to communicate securely with the server identified by the certificate. Using a certificate is a good way to prevent "man-in-the-middle" attacks, in which someone in between you and the server you think you are talking to is able to insert their own (harmful) content.
You can use Certbot to easily obtain and configure a free certificate from Let's Encrypt, a joint project of EFF, Mozilla, and many other sponsors.
Certificates and Lineages Certbot introduces the concept of a lineage, which is a collection of all the versions of a certificate plus Certbot configuration information maintained for that certificate from renewal to renewal. Whenever you renew a certificate, Certbot keeps the same configuration unless you explicitly change it, for example by adding or removing domains. If you add domains, you can either add them to an existing lineage or create a new one.
See also: updating_certs
Table of Contents • About Certbot
• System Requirements
• Alternate installation methods
• Snap
• Certbot-Auto
• Problems with Python virtual environment
• Running with Docker
• Operating System Packages
• Installing from source
About Certbot Certbot is meant to be run directly on a web server, normally by a system administrator. In most cases, running Certbot on your personal computer is not a useful option. The instructions below relate to installing and running Certbot on a server.
System administrators can use Certbot directly to request certificates; they should not allow unprivileged users to run arbitrary Certbot commands as root, because Certbot allows its user to specify arbitrary file locations and run arbitrary scripts.
Certbot is packaged for many common operating systems and web servers. Check whether certbot (or letsencrypt) is packaged for your web server's OS by visiting certbot.eff.org, where you will also find the correct installation instructions for your system.
NOTE: Unless you have very specific requirements, we kindly suggest that you use the installation instructions for your system found at certbot.eff.org.