neulab/tldr huggingface dataset:
singularity-build(1), singularity-cache(1), singularity-capability(1), singularity-config(1), singularity-delete(1), singularity-exec(1), singularity-inspect(1), singularity-instance(1), singularity-key(1), singularity-oci(1), singularity-overlay(1), singularity-plugin(1), singularity-pull(1), singularity-push(1), singularity-remote(1), singularity-run(1), singularity-run-help(1), singularity-search(1), singularity-shell(1), singularity-sif(1), singularity-sign(1), singularity-test(1), singularity-verify(1), singularity-version(1)
29-Nov-2021 Auto generated by spf13/cobra
PARTPROBE(8)                    GNU Parted Manual                   PARTPROBE(8)
partprobe - inform the OS of partition table changes
partprobe [-d] [-s] [devices...]
This manual page documents briefly the partprobe command.
partprobe is a program that informs the operating system kernel of partition table changes.
This program uses short UNIX style options.
-d, --dry-run Don't update the kernel.
-s, --summary Show a summary of devices and their partitions.
Report bugs to <bug-parted@gnu.org>
parted(8).
This manual page was written by Timshel Knoll <timshel@debian.org>, for the Debian GNU/Linux system (but may be used by others).
LLDB(1)                               LLDB                               LLDB(1)
lldb - LLDB Documentation
lldb [options] executable
lldb is a next generation, high-performance debugger. It is built as a set of reusable components which highly leverage existing libraries in the larger LLVM Project, such as the Clang expression parser and LLVM disassembler.
lldb is the default debugger in Xcode on macOS and supports debugging C, Objective-C and C++ on the desktop and iOS devices and simulator.
All of the code in the LLDB project is available under the Apache 2.0 License with LLVM exceptions.
--attach-name <name> Tells the debugger to attach to a process with the given name.
--attach-pid <pid> Tells the debugger to attach to a process with the given pid.
-n <value> Alias for --attach-name
-p <value> Alias for --attach-pid
--wait-for Tells the debugger to wait for a process with the given pid or name to launch before attaching.
-w     Alias for --wait-for
--batch Tells the debugger to run the commands from -s, -S, -o & -O, and then quit.
-b     Alias for --batch
-K <value> Alias for --source-on-crash
-k <value> Alias for --one-line-on-crash
--local-lldbinit Allow the debugger to parse the .lldbinit files in the current working directory, unless --no-lldbinit is passed.
--no-lldbinit Do not automatically parse any '.lldbinit' files.
--one-line-before-file <command> Tells the debugger to execute this one-line lldb command before any file provided on the command line has been loaded.
--one-line-on-crash <command> When in batch mode, tells the debugger to run this one-line lldb command if the target crashes.
--one-line <command> Tells the debugger to execute this one-line lldb command after any file provided on the command line has been loaded.
-O <value> Alias for --one-line-before-file
-o <value> Alias for --one-line
-Q     Alias for --source-quietly
--source-before-file <file> Tells the debugger to read in and execute the lldb commands in the given file, before any file has been loaded.
--source-on-crash <file> When in batch mode, tells the debugger to source this file of lldb commands if the target crashes.
--source-quietly Tells the debugger to execute this one-line lldb command before any file has been loaded.
--source <file> Tells the debugger to read in and execute the lldb commands in the given file, after any file has been loaded.
-S <value> Alias for --source-before-file
-s <value> Alias for --source
-x     Alias for --no-lldbinit
--arch <architecture> Tells the debugger to use the specified architecture when starting and running the program.
-a <value> Alias for --arch
--capture-path <filename> Tells the debugger to use the given filename for the reproducer.
--capture Tells the debugger to capture a reproducer.
--core <filename> Tells the debugger to use the full path to <filename> as the core file.
-c <value> Alias for --core
--debug Tells the debugger to print out extra information for debugging itself.
-d     Alias for --debug
--editor Tells the debugger to open source files using the host's "external editor" mechanism.
-e     Alias for --editor
--file <filename> Tells the debugger to use the file <filename> as the program to be debugged.
-f <value> Alias for --file
--help Prints out the usage information for the LLDB debugger.
-h     Alias for --help
--no-use-colors Do not use colors.
--replay <filename> Tells the debugger to replay a reproducer from <filename>.
--version Prints out the current version number of the LLDB debugger.
-v     Alias for --version
-X     Alias for --no-use-color
-r=<flags> Alias for --repl=<flags>
--repl-language <language> Chooses the language for the REPL.
--repl=<flags> Runs lldb in REPL mode with a stub process with the given flags.
-R <value> Alias for --repl-language
-l <value> Alias for --script-language
--python-path Prints out the path to the lldb.py file for this version of lldb.
-P     Alias for --python-path
--script-language <language> Tells the debugger to use the specified scripting language for user-defined scripts.
The debugger can be started in several modes.
Passing an executable as a positional argument prepares lldb to debug the given executable. To disambiguate between arguments passed to lldb and arguments passed to the debugged executable, arguments starting with a - must be passed after --. lldb --arch x86_64 /path/to/program program argument -- --arch armv7
For convenience, passing the executable after -- is also supported. lldb --arch x86_64 -- /path/to/program program argument --arch armv7
Passing one of the attach options causes lldb to immediately attach to the given process. lldb -p <pid> lldb -n <process-name>
Passing --repl starts lldb in REPL mode. lldb -r
Passing --core causes lldb to debug the core file. lldb -c /path/to/core
Command options can be combined with these modes and cause lldb to run the specified commands before or after events, like loading the file or crashing, in the order provided on the command line. lldb -O 'settings set stop-disassembly-count 20' -o 'run' -o 'bt' lldb -S /source/before/file -s /source/after/file lldb -K /source/before/crash -k /source/after/crash
Note: In REPL mode no file is loaded, so commands specified to run after loading the file (via -o or -s) will be ignored.
In lldb there is a help command which can be used to find descriptions and examples of all lldb commands.  To get help on "breakpoint set" you would type "help breakpoint set".
There is also an apropos command which will search the help text of all commands for a given term ‐‐ this is useful for locating a command by topic.  For instance, "apropos breakpoint" will list any command that has the word "breakpoint" in its help text.
lldb reads things like settings, aliases and commands from the .lldbinit file.
First, lldb will try to read the application specific init file whose name is ~/.lldbinit followed by a "-" and the name of the current program. This would be ~/.lldbinit-lldb for the command line lldb and ~/.lldbinit-Xcode for Xcode. If there is no application specific init file, lldb will look for an init file in the home directory.  If launched with a REPL option, it will first look for a REPL configuration file, specific to the REPL language. The init file should be named as follow: .lldbinit-<language>-repl (i.e. .lldbinit-swift-repl). If this file doesn't exist, or lldb wasn't launch with REPL, meaning there is neither a REPL init file nor an application specific init file, lldb will fallback to the global ~/.lldbinit.
Secondly, it will look for an .lldbinit file in the current working directory.  For security reasons, lldb will print a warning and not source this file by default. This behavior can be changed by changing the target.load-cwd-lldbinit setting.
To always load the .lldbinit file in the current working directory, add the following command to ~/.lldbinit: settings set target.load-cwd-lldbinit true
To never load the .lldbinit file in the current working directory and silence the warning, add the following command to ~/.lldbinit: settings set target.load-cwd-lldbinit false
The LLDB project page https://lldb.llvm.org has many different resources for lldb users ‐‐ the gdb/lldb command equivalence page https://lldb.llvm.org/use/map.html can be especially helpful for users coming from gdb.
LLVM project
2007-2021, The LLDB Team
PVS(8)                       System Manager's Manual                      PVS(8)
pvs â€” Display information about physical volumes
pvs [ option_args ] [ position_args ]
pvs produces formatted output about PVs.
pvs [ -a|--all ] [ -o|--options String ] [ -S|--select String ] [ -O|--sort String ] [    --segments ] [    --aligned ] [    --binary ] [    --configreport log|vg|lv|pv|pvseg|seg ] [    --foreign ] [    --ignorelockingfailure ] [    --logonly ] [    --nameprefixes ] [    --noheadings ] [    --nosuffix ] [    --readonly ] [    --reportformat basic|json ] [    --rows ] [    --separator String ] [    --shared ] [    --unbuffered ] [    --units [Number]r|R|h|H|b|B|s|S|k|K|m|M|g|G|t|T|p|P|e|E ] [    --unquoted ] [ COMMON_OPTIONS ] [ PV|Tag ... ]
--segments Produces one line of output for each contiguous allocation of space on each PV, showing the start (pvseg_start) and length (pvseg_size) in units of physical extents.
The pv_attr bits are:
1  (d)uplicate, (a)llocatable, (u)sed
2  e(x)ported
3  (m)issing
micro(1)                     General Commands Manual                    micro(1)
micro - A modern and intuitive terminal-based text editor
micro [OPTIONS] [FILE]...
Micro is a terminal-based text editor that aims to be easy to use and intuitive, while also taking advantage of the full capabilities of modern terminals. It comes as one single, batteries-included, static binary with no dependencies.
As the name indicates, micro aims to be somewhat of a successor to the nano editor by being easy to install and use in a pinch, but micro also aims to be enjoyable to use full time, whether you work in the terminal because you prefer it (like me), or because you need to (over ssh).
Use Ctrl-q to quit, Ctrl-s to save, and Ctrl-g to open the in-editor help menu.
-clean Cleans the configuration directory
-config-dir dir Specify a custom location for the configuration directory
[FILE]:LINE:COL Specify a line and column to start the cursor at when opening a buffer
-options Show all option help
-debug Enable debug mode (enables logging to ./log.txt)
-version Show the version number and information
Micro's plugins can be managed at the command line with the following commands.
-plugin remove [PLUGIN]... Remove plugin(s)
-plugin update [PLUGIN]... Update plugin(s) (if no argument is given, updates all plugins)
-plugin search [PLUGIN]... Search for a plugin
-plugin list List installed plugins
-plugin available List available plugins
Micro's options can also be set via command line arguments for quick adjustments. For real configuration, please use the settings.json file (see 'help options').
-option value Set `option` to `value` for this session For example: `micro -syntax off file.c`
Micro uses $MICRO_CONFIG_HOME as the configuration directory.  If this environment variable is not set, it uses $XDG_CONFIG_HOME/micro instead. If that environment variable is not set, it uses ~/.config/micro as the configuration directory.  In the documentation, we use ~/.config/micro to refer to the configuration directory (even if it may in fact be somewhere else if you have set either of the above environment variables).
This manpage is intended only to serve as a quick guide to the invocation of micro and is not intended to replace the full documentation included with micro which can be accessed from within micro. Micro tells you what key combination to press to get help in the lower right.
A comprehensive list of bugs will not be listed in this manpage. See the Github page at https://github.com/zyedidia/micro/issues for a list of known bugs and to report any newly encountered bugs you may find. We strive to correct bugs as swiftly as possible.
Copyright Â© 2020 Zachary Yedidia, et al. MIT license.  See https://github.com/zyedidia/micro for details.
HOMECTL(1)                           homectl                          HOMECTL(1)
homectl - Create, remove, change or inspect home directories
homectl [OPTIONS...] {COMMAND} [NAME...]
homectl may be used to create, remove, change or inspect a user's home directory. It's primarily a command interfacing with systemd- homed.service(8) which manages home directories of users.
Home directories managed by systemd-homed.service are self-contained, and thus include the user's full metadata record in the home's data storage itself, making them easy to migrate between machines. In particular, a home directory describes a matching user record, and every user record managed by systemd-homed.service also implies existence and encapsulation of a home directory. The user account and home directory become the same concept.
The following backing storage mechanisms are supported:
•   An individual LUKS2 encrypted loopback file for a user, stored in /home/*.home. At login the file system contained in this files is mounted, after the LUKS2 encrypted volume has been attached. The user's password is identical to the encryption passphrase of the LUKS2 volume. Access to data without preceding user authentication is thus not possible, even for the system administrator. This storage mechanism provides the strongest data security and is thus recommended.
•   Similar, but the LUKS2 encrypted file system is located on regular block device, such as an USB storage stick. In this mode home directories and all data they include are nicely migratable between machines, simply by plugging the USB stick into different systems at different times.
•   An encrypted directory using "fscrypt" on file systems that support it (at the moment this is primarily "ext4"), located in /home/*.homedir. This mechanism also provides encryption, but substantially weaker than LUKS2, as most file system metadata is unprotected. Moreover it currently does not support changing user passwords once the home directory has been created.
•   A "btrfs" subvolume for each user, also located in /home/*.homedir. This provides no encryption, but good quota support.
•   A regular directory for each user, also located in /home/*.homedir. This provides no encryption, but is a suitable fallback available on all machines, even where LUKS2, "fscrypt" or "btrfs" support is not available.
•   An individual Windows file share (CIFS) for each user.
Note that systemd-homed.service and homectl will not manage "classic" UNIX user accounts as created with useradd(8) or similar tools. In particular, this functionality is not suitable for managing system users (i.e. users with a UID below 1000) but is exclusive to regular ("human") users.
Note that users/home directories managed via systemd-homed.service do not show up in /etc/passwd and similar files, they are synthesized via glibc NSS during runtime. They are thus resolvable and may be enumerated via the getent(1) tool.
This tool interfaces directly with systemd-homed.service, and may execute specific commands on the home directories it manages. Since every home directory managed that way also defines a JSON user and group record these home directories may also be inspected and enumerated via userdbctl(1).
Home directories managed by systemd-homed.service are usually in one of two states, or in a transition state between them: when "active" they are unlocked and mounted, and thus accessible to the system and its programs; when "inactive" they are not mounted and thus not accessible. Activation happens automatically at login of the user and usually can only complete after a password (or other authentication token) has been supplied. Deactivation happens after the user fully logged out. A home directory remains active as long as the user is logged in at least once, i.e. has at least one login session. When the user logs in a second time simultaneously the home directory remains active. It is deactivated only after the last of the user's sessions ends.
The following general options are understood (further options that control the various properties of user records managed by systemd-homed.service are documented further down):
--identity=FILE Read the user's JSON record from the specified file. If passed as "-" read the user record from standard input. The supplied JSON object must follow the structure documented in JSON User Records[1]. This option may be used in conjunction with the create and update commands (see below), where it allows configuring the user record in JSON as-is, instead of setting the individual user record properties (see below).
--json=FORMAT, -J Controls whether to output the user record in JSON format, if the inspect command (see below) is used. Takes one of "pretty", "short" or "off". If "pretty" human-friendly whitespace and newlines are inserted in the output to make the JSON data more readable. If "short" all superfluous whitespace is suppressed. If "off" (the default) the user information is not shown in JSON format but in a friendly human readable formatting instead. The -J option picks "pretty" when run interactively and "short" otherwise.
--export-format=FORMAT, -E, -EE When used with the inspect verb in JSON mode (see above) may be used to suppress certain aspects of the JSON user record on output. Specifically, if "stripped" format is used the binding and runtime fields of the record are removed. If "minimal" format is used the cryptographic signature is removed too. If "full" format is used the full JSON record is shown (this is the default). This option is useful for copying an existing user record to a different system in order to create a similar user there with the same settings. Specifically: homectl inspect -EE | ssh root@othersystem homectl create -i- may be used as simple command line for replicating a user on another host.  -E is equivalent to -j --export-format=stripped, -EE to -j --export-format=minimal. Note that when replicating user accounts user records acquired in "stripped" mode will retain the original cryptographic signatures and thus may only be modified when the private key to update them is available on the destination machine. When replicating users in "minimal" mode, the signature is removed during the replication and thus the record will be implicitly signed with the key of the destination machine and may be updated there without any private key replication.
--no-legend Do not print the legend, i.e. column headers and the footer with hints.
The following options control various properties of the user records/home directories that systemd-homed.service manages. These switches may be used in conjunction with the create and update commands for configuring various aspects of the home directory and the user account:
--real-name=NAME, -c NAME The real name for the user. This corresponds with the GECOS field on classic UNIX NSS records.
--realm=REALM The realm for the user. The realm associates a user with a specific organization or installation, and allows distinguishing users of the same name defined in different contexts. The realm can be any string that also qualifies as valid DNS domain name, and it is recommended to use the organization's or installation's domain name for this purpose, but this is not enforced nor required. On each system only a single user of the same name may exist, and if a user with the same name and realm is seen it is assumed to refer to the same user while a user with the same name but different realm is considered a different user. Note that this means that two users sharing the same name but with distinct realms are not allowed on the same system. Assigning a realm to a user is optional.
--email-address=EMAIL Takes an electronic mail address to associate with the user. On log-in the $EMAIL environment variable is initialized from this value.
--location=TEXT Takes location specification for this user. This is free-form text, which might or might not be usable by geo-location applications. Example: --location="Berlin, Germany" or --location="Basement, Room 3a"
--icon-name=ICON Takes an icon name to associate with the user, following the scheme defined by the Icon Naming Specification[2].
--home-dir=PATH, -dPATH Takes a path to use as home directory for the user. Note that this is the directory the user's home directory is mounted to while the user is logged in. This is not where the user's data is actually stored, see --image-path= for that. If not specified defaults to /home/$USER.
--uid=UID Takes a preferred numeric UNIX UID to assign this user. If a user is to be created with the specified UID and it is already taken by a different user on the local system then creation of the home directory is refused. Note though, if after creating the home directory it is used on a different system and the configured UID is taken by another user there, then systemd-homed may assign the user a different UID on that system. The specified UID must be outside of the system user range. It is recommended to use the 60001...60513 UID range for this purpose. If not specified, the UID is automatically picked. If the home directory is found to be owned by a different UID when logging in, the home directory and everything underneath it will have its ownership changed automatically before login completes.
Note that users managed by systemd-homed always have a matching group associated with the same name as well as a GID matching the UID of the user. Thus, configuring the GID separately is not permitted.
--member-of=GROUP, -G GROUP Takes a comma-separated list of auxiliary UNIX groups this user shall belong to. Example: --member-of=wheel to provide the user with administrator privileges. Note that systemd-homed does not manage any groups besides a group matching the user in name and numeric UID/GID. Thus any groups listed here must be registered independently, for example with groupadd(8). Any non-existent groups are ignored. This option may be used more than once, in which case all specified group lists are combined. If the user is currently a member of a group which is not listed, the user will be removed from the group.
--skel=PATH Takes a file system path to a directory. Specifies the skeleton directory to initialize the home directory with. All files and directories in the specified path are copied into any newly create home directory. If not specified defaults to /etc/skel/.
--shell=SHELL Takes a file system path. Specifies the shell binary to execute on terminal logins. If not specified defaults to /bin/bash.
--setenv=VARIABLE=VALUE Takes an environment variable assignment to set for all user processes. Note that a number of other settings also result in environment variables to be set for the user, including --email=, --timezone= and --language=. May be used multiple times to set multiple environment variables.
--timezone=TIMEZONE Takes a time zone location name that sets the timezone for the specified user. When the user logs in the $TZ environment variable is initialized from this setting. Example: --timezone=Europe/Amsterdam will result in the environment variable "TZ=:Europe/Amsterdam". (":" is used intentionally as part of the timezone specification, see tzset(3).)
--language=LANG Takes a specifier indicating the preferred language of the user. The $LANG environment variable is initialized from this value on login, and thus a value suitable for this environment variable is accepted here, for example --language=de_DE.UTF8.
--ssh-authorized-keys=KEYS Either takes a SSH authorized key line to associate with the user record or a "@" character followed by a path to a file to read one or more such lines from. SSH keys configured this way are made available to SSH to permit access to this home directory and user record. This option may be used more than once to configure multiple SSH keys.
--pkcs11-token-uri=URI Takes an RFC 7512 PKCS#11 URI referencing a security token (e.g. YubiKey or PIV smartcard) that shall be able to unlock the user account. The security token URI should reference a security token with exactly one pair of X.509 certificate and private key. A random secret key is then generated, encrypted with the public key of the X.509 certificate, and stored as part of the user record. At login time it is decrypted with the PKCS#11 module and then used to unlock the account and associated resources. See below for an example how to set up authentication with a security token.
Instead of a valid PKCS#11 URI, the special strings "list" and "auto" may be specified. If "list" is passed, a brief table of suitable, currently plugged in PKCS#11 hardware tokens is shown, along with their URIs. If "auto" is passed, a suitable PKCS#11 hardware token is automatically selected (this operation will fail if there isn't exactly one suitable token discovered). The latter is a useful shortcut for the most common case where a single PKCS#11 hardware token is plugged in.
Note that many hardware security tokens implement both PKCS#11/PIV and FIDO2 with the "hmac-secret" extension (for example: the YubiKey 5 series), as supported with the --fido2-device= option below. Both mechanisms are similarly powerful, though FIDO2 is the more modern technology. PKCS#11/PIV tokens have the benefit of being recognizable before authentication and hence can be used for implying the user identity to use for logging in, which FIDO2 does not allow. PKCS#11/PIV devices generally require initialization (i.e. storing a private/public key pair on them, see example below) before they can be used; FIDO2 security tokens generally do not required that, and work out of the box.
--fido2-device=PATH Takes a path to a Linux "hidraw" device (e.g.  /dev/hidraw1), referring to a FIDO2 security token implementing the "hmac-secret" extension that shall be able to unlock the user account. A random salt value is generated on the host and passed to the FIDO2 device, which calculates a HMAC hash of the salt using an internal secret key. The result is then used as the key to unlock the user account. The random salt is included in the user record, so that whenever authentication is needed it can be passed to the FIDO2 token again.
Instead of a valid path to a FIDO2 "hidraw" device the special strings "list" and "auto" may be specified. If "list" is passed, a brief table of suitable discovered FIDO2 devices is shown. If "auto" is passed, a suitable FIDO2 token is automatically selected, if exactly one is discovered. The latter is a useful shortcut for the most common case where a single FIDO2 hardware token is plugged in.
Note that FIDO2 devices suitable for this option must implement the "hmac-secret" extension. Most current devices (such as the YubiKey 5 series) do. If the extension is not implemented the device cannot be used for unlocking home directories.
Note that many hardware security tokens implement both FIDO2 and PKCS#11/PIV (and thus may be used with either --fido2-device= or --pkcs11-token-uri=), for a discussion see above.
--fido2-with-client-pin=BOOL When enrolling a FIDO2 security token, controls whether to require the user to enter a PIN when unlocking the account (the FIDO2 "clientPin" feature). Defaults to "yes". (Note: this setting is without effect if the security token does not support the "clientPin" feature at all, or does not allow enabling or disabling it.)
--fido2-with-user-presence=BOOL When enrolling a FIDO2 security token, controls whether to require the user to verify presence (tap the token, the FIDO2 "up" feature) when unlocking the account. Defaults to "yes". (Note: this setting is without effect if the security token does not support the "up" feature at all, or does not allow enabling or disabling it.)
--fido2-with-user-verification=BOOL When enrolling a FIDO2 security token, controls whether to require user verification when unlocking the account (the FIDO2 "uv" feature). Defaults to "no". (Note: this setting is without effect if the security token does not support the "uv" feature at all, or does not allow enabling or disabling it.)
--recovery-key=BOOL Accepts a boolean argument. If enabled a recovery key is configured for the account. A recovery key is a computer generated access key that may be used to regain access to an account if the password has been forgotten or the authentication token lost. The key is generated and shown on screen, and should be printed or otherwise transferred to a secure location. A recovery key may be entered instead of a regular password to unlock the account.
--locked=BOOLEAN Takes a boolean argument. Specifies whether this user account shall be locked. If true logins into this account are prohibited, if false (the default) they are permitted (of course, only if authorization otherwise succeeds).
--not-before=TIMESTAMP, --not-after=TIMESTAMP These options take a timestamp string, in the format documented in systemd.time(7) and configures points in time before and after logins into this account are not permitted.
--rate-limit-interval=SECS, --rate-limit-burst=NUMBER Configures a rate limit on authentication attempts for this user. If the user attempts to authenticate more often than the specified number, on a specific system, within the specified time interval authentication is refused until the time interval passes. Defaults to 10 times per 1min.
--password-hint=TEXT Takes a password hint to store alongside the user record. This string is stored accessible only to privileged users and the user itself and may not be queried by other users. Example: --password-hint="My first pet's name".
--enforce-password-policy=BOOL, -P Takes a boolean argument. Configures whether to enforce the system's password policy for this user, regarding quality and strength of selected passwords. Defaults to on.  -P is short for ---enforce-password-policy=no.
--password-change-now=BOOL Takes a boolean argument. If true the user is asked to change their password on next login.
--password-change-min=TIME, --password-change-max=TIME, --password-change-warn=TIME, --password-change-inactive=TIME Each of these options takes a time span specification as argument (in the syntax documented in systemd.time(7)) and configures various aspects of the user's password expiration policy. Specifically, --password-change-min= configures how much time has to pass after changing the password of the user until the password may be changed again. If the user tries to change their password before this time passes the attempt is refused.  --password-change-max= configures how soon after it has been changed the password expires and needs to be changed again. After this time passes logging in may only proceed after the password is changed.  --password-change-warn= specifies how much earlier than then the time configured with --password-change-max= the user is warned at login to change their password as it will expire soon. Finally --password-change-inactive= configures the time which has to pass after the password as expired until the user is not permitted to log in or change the password anymore. Note that these options only apply to password authentication, and do not apply to other forms of authentication, for example PKCS#11-based security token authentication.
--disk-size=BYTES Either takes a size in bytes as argument (possibly using the usual K, M, G, ... suffixes for 1024 base values), or a percentage value and configures the disk space to assign to the user. If a percentage value is specified (i.e. the argument suffixed with "%") it is taken relative to the available disk space of the backing file system. If the LUKS2 backend is used this configures the size of the loopback file and file system contained therein. For the other storage backends configures disk quota using the filesystem's native quota logic, if available. If not specified, defaults to 85% of the available disk space for the LUKS2 backend and to no quota for the others.
--access-mode=MODE Takes a UNIX file access mode written in octal. Configures the access mode of the home directory itself. Note that this is only used when the directory is first created, and the user may change this any time afterwards. Example: --access-mode=0700
--umask=MASK Takes the access mode mask (in octal syntax) to apply to newly created files and directories of the user ("umask"). If set this controls the initial umask set for all login sessions of the user, possibly overriding the system's defaults.
--nice=NICE Takes the numeric scheduling priority ("nice level") to apply to the processes of the user at login time. Takes a numeric value in the range -20 (highest priority) to 19 (lowest priority).
--rlimit=LIMIT=VALUE[:VALUE] Allows configuration of resource limits for processes of this user, see getrlimit(2) for details. Takes a resource limit name (e.g. "LIMIT_NOFILE") followed by an equal sign, followed by a numeric limit. Optionally, separated by colon a second numeric limit may be specified. If two are specified this refers to the soft and hard limits, respectively. If only one limit is specified the setting sets both limits in one.
--tasks-max=TASKS Takes a non-zero unsigned integer as argument. Configures the maximum number of tasks (i.e. threads, where each process is at least one thread) the user may have at any given time. This limit applies to all tasks forked off the user's sessions, even if they change user identity via su(1) or a similar tool. Use --rlimit=LIMIT_NPROC= to place a limit on the tasks actually running under the UID of the user, thus excluding any child processes that might have changed user identity. This controls the TasksMax= setting of the per-user systemd slice unit user-$UID.slice. See systemd.resource-control(5) for further details.
--memory-high=BYTES, --memory-max=BYTES Set a limit on the memory a user may take up on a system at any given time in bytes (the usual K, M, G, ... suffixes are supported, to the base of 1024). This includes all memory used by the user itself and all processes they forked off that changed user credentials. This controls the MemoryHigh= and MemoryMax= settings of the per-user systemd slice unit user-$UID.slice. See systemd.resource-control(5) for further details.
--cpu-weight=WEIGHT, --io-weight=WEIGHT Set CPU and IO scheduling weights of the processes of the user, including those of processes forked off by the user that changed user credentials. Takes a numeric value in the range 1...10000. This controls the CPUWeight= and IOWeight= settings of the per-user systemd slice unit user-$UID.slice. See systemd.resource-control(5) for further details.
--storage=STORAGE Selects the storage mechanism to use for this home directory. Takes one of "luks", "fscrypt", "directory", "subvolume", "cifs". For details about these mechanisms, see above. If a new home directory is created and the storage type is not specifically specified, homed.conf(5) defines which default storage to use.
--image-path=PATH Takes a file system path. Configures where to place the user's home directory. When LUKS2 storage is used refers to the path to the loopback file, otherwise to the path to the home directory (which may be in /home/ or any other accessible filesystem). When unspecified defaults to /home/$USER.home when LUKS storage is used and /home/$USER.homedir for the other storage mechanisms. Not defined for the "cifs" storage mechanism. To use LUKS2 storage on a regular block device (for example a USB stick) pass the path to the block device here. Specifying the path to a directory here when using LUKS2 storage is not allowed. Similar, specifying the path to a regular file or device node is not allowed if any of the other storage backends are used.
--fs-type=TYPE When LUKS2 storage is used configures the file system type to use inside the home directory LUKS2 container. One of "btrfs", "ext4", "xfs". If not specified homed.conf(5) defines which default file system type to use. Note that "xfs" is not recommended as its support for file system resizing is too limited.
--luks-discard=BOOL When LUKS2 storage is used configures whether to enable the "discard" feature of the file system. If enabled the file system on top of the LUKS2 volume will report empty block information to LUKS2 and the loopback file below, ensuring that empty space in the home directory is returned to the backing file system below the LUKS2 volume, resulting in a "sparse" loopback file. This option mostly defaults to off, since this permits over-committing home directories which results in I/O errors if the underlying file system runs full while the upper file system wants to allocate a block. Such I/O errors are generally not handled well by file systems nor applications. When LUKS2 storage is used on top of regular block devices (instead of on top a loopback file) the discard logic defaults to on.
--luks-offline-discard=BOOL Similar to --luks-discard=, controls the trimming of the file system. However, while --luks-discard= controls what happens when the home directory is active, --luks-offline-discard= controls what happens when it becomes inactive, i.e. whether to trim/allocate the storage when deactivating the home directory. This option defaults to on, to ensure disk space is minimized while a user is not logged in.
--luks-cipher=CIPHER, --luks-cipher-mode=MODE, --luks-volume-key-size=BITS, --luks-pbkdf-type=TYPE, --luks-pbkdf-hash-algorithm=ALGORITHM, --luks-pbkdf-time-cost=SECONDS, --luks-pbkdf-memory-cost=BYTES, --luks-pbkdf-parallel-threads=THREADS Configures various cryptographic parameters for the LUKS2 storage mechanism. See cryptsetup(8) for details on the specific attributes.
--nosuid=BOOL, --nodev=BOOL, --noexec=BOOL Configures the "nosuid", "nodev" and "noexec" mount options for the home directories. By default "nodev" and "nosuid" are on, while "noexec" is off. For details about these mount options see mount(8).
--cifs-domain=DOMAIN, --cifs-user-name=USER, --cifs-service=SERVICE Configures the Windows File Sharing (CIFS) domain and user to associate with the home directory/user account, as well as the file share ("service") to mount as directory. The latter is used when "cifs" storage is selected.
--stop-delay=SECS Configures the time the per-user service manager shall continue to run after the all sessions of the user ended. The default is configured in logind.conf(5) (for home directories of LUKS2 storage located on removable media this defaults to 0 though). A longer time makes sure quick, repetitive logins are more efficient as the user's service manager doesn't have to be started every time.
--kill-processes=BOOL Configures whether to kill all processes of the user on logout. The default is configured in logind.conf(5).
--auto-login=BOOL Takes a boolean argument. Configures whether the graphical UI of the system should automatically log this user in if possible. Defaults to off. If less or more than one user is marked this way automatic login is disabled.
list List all home directories (along with brief details) currently managed by systemd-homed.service. This command is also executed if none is specified on the command line. (Note that the list of users shown by this command does not include users managed by other subsystems, such as system users or any traditional users listed in /etc/passwd.)
activate USER [USER...] Activate one or more home directories. The home directories of each listed user will be activated and made available under their mount points (typically in /home/$USER). Note that any home activated this way stays active indefinitely, until it is explicitly deactivated again (with deactivate, see below), or the user logs in and out again and it thus is deactivated due to the automatic deactivation-on-logout logic.
Activation of a home directory involves various operations that depend on the selected storage mechanism. If the LUKS2 mechanism is used, this generally involves: inquiring the user for a password, setting up a loopback device, validating and activating the LUKS2 volume, checking the file system, mounting the file system, and potentially changing the ownership of all included files to the correct UID/GID.
deactivate USER [USER...] Deactivate one or more home directories. This undoes the effect of activate.
inspect USER [USER...] Show various details about the specified home directories. This shows various information about the home directory and its user account, including runtime data such as current state, disk use and similar. Combine with --json= to show the detailed JSON user record instead, possibly combined with --export-format= to suppress certain aspects of the output.
authenticate USER [USER...] Validate authentication credentials of a home directory. This queries the caller for a password (or similar) and checks that it correctly unlocks the home directory. This leaves the home directory in the state it is in, i.e. it leaves the home directory in inactive state if it was inactive before, and in active state if it was active before.
create USER, create --identity=PATH [USER] Create a new home directory/user account of the specified name. Use the various user record property options (as documented above) to control various aspects of the home directory and its user accounts.
The specified user name should follow the strict syntax described on User/Group Name Syntax[3].
remove USER Remove a home directory/user account. This will remove both the home directory's user record and the home directory itself, and thus delete all files and directories owned by the user.
update USER, update --identity=PATH [USER] Update a home directory/user account. Use the various user record property options (as documented above) to make changes to the account, or alternatively provide a full, updated JSON user record via the --identity= option.
Note that changes to user records not signed by a cryptographic private key available locally are not permitted, unless --identity= is used with a user record that is already correctly signed by a recognized private key.
passwd USER Change the password of the specified home directory/user account.
resize USER BYTES Change the disk space assigned to the specified home directory. If the LUKS2 storage mechanism is used this will automatically resize the loopback file and the file system contained within. Note that if "ext4" is used inside of the LUKS2 volume, it is necessary to deactivate the home directory before shrinking it (i.e the user has to log out). Growing can be done while the home directory is active. If "xfs" is used inside of the LUKS2 volume the home directory may not be shrunk whatsoever. On all three of "ext4", "xfs" and "btrfs" the home directory may be grown while the user is logged in, and on the latter also shrunk while the user is logged in. If the "subvolume", "directory", "fscrypt" storage mechanisms are used, resizing will change file system quota.
lock USER Temporarily suspend access to the user's home directory and remove any associated cryptographic keys from memory. Any attempts to access the user's home directory will stall until the home directory is unlocked again (i.e. re-authenticated). This functionality is primarily intended to be used during system suspend to make sure the user's data cannot be accessed until the user re-authenticates on resume. This operation is only defined for home directories that use the LUKS2 storage mechanism.
unlock USER Resume access to the user's home directory again, undoing the effect of lock above. This requires authentication of the user, as the cryptographic keys required for access to the home directory need to be reacquired.
lock-all Execute the lock command on all suitable home directories at once. This operation is generally executed on system suspend (i.e. by systemctl suspend and related commands), to ensure all active user's cryptographic keys for accessing their home directories are removed from memory.
deactivate-all Execute the deactivate command on all active home directories at once. This operation is generally executed on system shut down (i.e. by systemctl poweroff and related commands), to ensure all active user's home directories are fully deactivated before /home/ and related file systems are unmounted.
with USER COMMAND... Activate the specified user's home directory, run the specified command (under the caller's identity, not the specified user's) and deactivate the home directory afterwards again (unless the user is logged in otherwise). This command is useful for running privileged backup scripts and such, but requires authentication with the user's credentials in order to be able to unlock the user's home directory.
When a command is invoked with with, the exit status of the child is propagated. Effectively, homectl will exit without error if the command is successfully invoked and finishes successfully.
Example 1. Create a user "waldo" in the administrator group "wheel", and assign 500 MiB disk space to them.
homectl create waldo --real-name="Waldo McWaldo" -G wheel --disk-size=500M
Example 2. Create a user "wally" on a USB stick, and assign a maximum of 500 concurrent tasks to them.
homectl create wally --real-name="Wally McWally" --image-path=/dev/disk/by-id/usb-SanDisk_Ultra_Fit_476fff954b2b5c44-0:0 --tasks-max=500
Example 3. Change nice level of user "odlaw" to +5 and make sure the environment variable $SOME is set to the string "THING" for them on login.
homectl update odlaw --nice=5 --setenv=SOME=THING
Example 4. Set up authentication with a YubiKey security token using PKCS#11/PIV:
# Clear the Yubikey from any old keys (careful!) ykman piv reset
# Generate a new private/public key pair on the device, store the public key in 'pubkey.pem'. ykman piv generate-key -a RSA2048 9d pubkey.pem
# Create a self-signed certificate from this public key, and store it on the device. ykman piv generate-certificate --subject "Knobelei" 9d pubkey.pem
# We don't need the public key on disk anymore rm pubkey.pem
# Allow the security token to unlock the account of user 'lafcadio'. homectl update lafcadio --pkcs11-token-uri=auto
Example 5. Set up authentication with a FIDO2 security token:
# Allow a FIDO2 security token to unlock the account of user 'nihilbaxter'. homectl update nihilbaxter --fido2-device=auto
systemd(1), systemd-homed.service(8), homed.conf(5), userdbctl(1), useradd(8), cryptsetup(8)
1. JSON User Records https://systemd.io/USER_RECORD
2. Icon Naming Specification https://standards.freedesktop.org/icon-naming-spec/icon-naming-spec-latest.html
3. User/Group Name Syntax https://systemd.io/USER_NAMES
MESG(1P)                    POSIX Programmer's Manual                   MESG(1P)
mesg — permit or deny messages
The mesg utility shall control whether other users are allowed to send messages via write, talk, or other utilities to a terminal device. The terminal device affected shall be determined by searching for the first terminal in the sequence of devices associated with standard input, standard output, and standard error, respectively. With no arguments, mesg shall report the current state without changing it. Processes with appropriate privileges may be able to send messages to the terminal independent of the current state.
The following operands shall be supported in the POSIX locale:
y         Grant permission to other users to send messages to the terminal device.
n         Deny permission to other users to send messages to the terminal device.
The following environment variables shall affect the execution of mesg:
LC_MESSAGES Determine the locale that should be used to affect the format and contents of diagnostic messages written (by mesg) to standard error.
If no operand is specified, mesg shall display the current terminal state in an unspecified format.
0    Receiving messages is allowed.
1    Receiving messages is not allowed.
The mechanism by which the message status of the terminal is changed is unspecified. Therefore, unspecified actions may cause the status of the terminal to change after mesg has successfully completed. These actions may include, but are not limited to: another invocation of the mesg utility, login procedures; invocation of the stty utility, invocation of the chmod utility or chmod() function, and so on.
The terminal changed by mesg is that associated with the standard input, output, or error, rather than the controlling terminal for the session. This is because users logged in more than once should be able to change any of their login terminals without having to stop the job running in those sessions.  This is not a security problem involving the terminals of other users because appropriate privileges would be required to affect the terminal of another user.