neulab/tldr huggingface dataset:
Using long date output formats may cause misalignment in shown columns if the length of the date exceeds the fixed size allocation.
Scaling an image when background transparency is enabled may not result in transparency being retained.
Teemu Toivola <tst at iki dot fi>
vnstat(1), vnstatd(8), vnstat.conf(5), units(7)
RC-SERVICE(8)                System Manager's Manual               RC-SERVICE(8)
rc-service â€” locate and run an OpenRC service with the given arguments
rc-service [-c, --ifcrashed] service cmd [...] rc-service -d, --debug service cmd [...] rc-service -D, --nodeps service cmd [...] rc-service [-i, --ifexists] service cmd [...] rc-service [-I, --ifinactive] service cmd [...] rc-service [-N, --ifnotstarted] service cmd [...] rc-service [-s, --ifstarted] service cmd [...] rc-service [-S, --ifstopped] service cmd [...] rc-service -e, --exists service rc-service -Z, --dry-run service cmd [...] rc-service -l, --list rc-service -r, --resolve service
Service scripts could be in different places on different systems. rc-service locates the specified service and runs it with the given arguments.  If -i, --ifexists is given then rc-service returns 0 even if the service does not exist.  If -I, --ifinactive or -N, --ifnotstarted is given then rc-service returns 0 if the service exists but is in the wrong state.
If given the -l, --list argument then rc-service will list all available services.
-e, --exists return 0 if it can find service, otherwise -1.  -r, --resolve does the same and also prints the full path of the service to stdout.
-d, --debug sets -x when running the service script(s).
-D, --nodeps ignores dependencies when running the service.
-Z, --dry-run displays commands rather than executing them.
openrc(8), stdout(3)
GIT-IGNORE(1)                      Git Extras                      GIT-IGNORE(1)
git-ignore - Add .gitignore patterns
git-ignore [<context>] [<pattern> [<pattern>]...]
Adds the given _pattern_s to a .gitignore file if it doesn´t already exist.
<context>
-l, --local
Sets the context to the .gitignore file in the current working directory. (default)
-g, --global
Sets the context to the global gitignore file for the current user.
-p, --private
Sets the context to the private exclude file for the repository (.git/info/exclude).
<pattern>
A space delimited list of patterns to append to the file in context.
PATTERN FORMAT Pattern format as described in the git manual
•   A blank line matches no files, so it can serve as a separator for readability. To append a blank line use empty quotes "".
•   A line starting with # serves as a comment. For example, "# This is a comment"
•   An optional prefix ! which negates the pattern; any matching file excluded by a previous pattern will become included again. If a negated pattern matches, this will override lower precedence patterns sources. To use an exclamation ! as command line argument it is best placed between single quotes ´´. For example, ´!src´
•   If the pattern ends with a slash, it is removed for the purpose of the following description, but it would only find a match with a directory. In other words, foo/ will match a directory foo and paths underneath it, but will not match a regular file or a symbolic link foo (this is consistent with the way how pathspec works in general in git).
•   If the pattern does not contain a slash /, git treats it as a shell glob pattern and checks for a match against the pathname relative to the location of the .gitignore file (relative to the top level of the work tree if not from a .gitignore file).
•   Otherwise, git treats the pattern as a shell glob suitable for consumption by fnmatch(3) with the FNM_PATHNAME flag: wildcards in the pattern will not match a / in the pathname. For example, "Documentation/*.html" matches "Documentation/git.html" but not "Documentation/ppc/ppc.html" or "tools/perf/Documentation/perf.html".
•   A leading slash matches the beginning of the pathname. For example, "/*.c" matches "cat-file.c" but not "mozilla-sha1/sha1.c".
All arguments are optional so calling git-ignore alone will display first the global then the local gitignore files:
$ git ignore Global gitignore: /home/alice/.gitignore # Numerous always-ignore extensions *.diff *.err *.orig *.rej *.swo *.swp *.vi *~ *.sass-cache
# OS or Editor folders `.DS_Store` `.Trashes` `._*` Thumbs.db --------------------------------- Local gitignore: .gitignore `.cache` `.project` `.settings` `.tmproj` nbproject
If you only want to see the global context use the --global argument (for local use --local):
$ git ignore Global gitignore: /home/alice/.gitignore `.DS_Store` `.Trashes` `._*` Thumbs.db
To quickly append a new pattern to the default/local context simply:
$ git ignore *.log Adding pattern(s) to: .gitignore `... adding ´*.log´`
You can now configure any patterns without ever using an editor, with a context and pattern arguments: The resulting configuration is also returned for your convenience.
$ git ignore --local "" "# Temporary files" *.tmp "*.log" tmp/*  "" "# Files I´d like to keep" ´!work´  "" Adding pattern(s) to: .gitignore `... adding ´´` `... adding ´# Temporary files´` `... adding ´index.tmp´` `... adding ´*.log´` `... adding ´tmp/*´` `... adding ´´` `... adding ´# Files I´d like to keep´` `... adding ´!work´` `... adding ´´`
Local gitignore: .gitignore
# Temporary files index.tmp *.log
# Files I´d like to keep !work
Written by Tj Holowaychuk <tj@vision-media.ca> and Tema Bolshakov <tweekane@gmail.com> and Nick Lombard <github@jigsoft.co.za>
MPD(1)                         Music Player Daemon                        MPD(1)
mpd - MPD documentation
mpd [options] [CONF_FILE]
MPD is a daemon for playing music. Music is played through the configured audio output(s) (which are generally local, but can be remote). The daemon stores info about all available music, and this info can be easily searched and retrieved. Player control, info retrieval, and playlist management can all be managed remotely.
MPD searches for a config file in $XDG_CONFIG_HOME/mpd/mpd.conf then ~/.mpdconf then ~/.mpd/mpd.conf then /etc/mpd.conf or uses CONF_FILE.
Read more about MPD at http://www.musicpd.org/
--help Output a brief help message.
--kill Kill the currently running mpd session. The pid_file parameter must be specified in the config file for this to work.
--no-config Don't read from the configuration file.
--no-daemon Don't detach from console.
--stderr Print messages to stderr.
--verbose Verbose logging.
--version Print version information.
$XDG_CONFIG_HOME/mpd/mpd.conf User configuration file (usually ~/.config/mpd/mpd.conf).
/etc/mpd.conf Global configuration file.
mpd.conf(5), mpc(1)
If you find a bug, please report it at https://github.com/MusicPlayerDaemon/MPD/issues/
Max Kellermann
2003-2021 The Music Player Daemon Project
CHATTR(1)                    General Commands Manual                   CHATTR(1)
chattr - change file attributes on a Linux file system
chattr [ -RVf ] [ -v version ] [ -p project ] [ mode ] files...
chattr changes the file attributes on a Linux file system.
The format of a symbolic mode is +-=[aAcCdDeFijmPsStTux].
The operator '+' causes the selected attributes to be added to the existing attributes of the files; '-' causes them to be removed; and '=' causes them to be the only attributes that the files have.
The letters 'aAcCdDeFijmPsStTux' select the new attributes for the files: append only (a), no atime updates (A), compressed (c), no copy on write (C), no dump (d), synchronous directory updates (D), extent format (e), case-insensitive directory lookups (F), immutable (i), data journaling (j), don't compress (m), project hierarchy (P), secure deletion (s), synchronous updates (S), no tail-merging (t), top of directory hierarchy (T), undeletable (u), and direct access for files (x).
The following attributes are read-only, and may be listed by lsattr(1) but not modified by chattr: encrypted (E), indexed directory (I), inline data (N), and verity (V).
Not all flags are supported or utilized by all file systems; refer to file system-specific man pages such as btrfs(5), ext4(5), and xfs(5) for more file system-specific details.
-R     Recursively change attributes of directories and their contents.
-V     Be verbose with chattr's output and print the program version.
-f     Suppress most error messages.
-v version Set the file's version/generation number.
-p project Set the file's project number.
a      A file with the 'a' attribute set can only be opened in append mode for writing.  Only the superuser or a process possessing the CAP_LINUX_IMMUTABLE capability can set or clear this attribute.
A      When a file with the 'A' attribute set is accessed, its atime record is not modified.  This avoids a certain amount of disk I/O for laptop systems.
c      A file with the 'c' attribute set is automatically compressed on the disk by the kernel.  A read from this file returns uncompressed data.  A write to this file compresses data before storing them on the disk.  Note: please make sure to read the bugs and limitations section at the end of this document.  (Note: For btrfs, If the 'c' flag is set, then the 'C' flag cannot be set. Also conflicts with btrfs mount option 'nodatasum')
C      A file with the 'C' attribute set will not be subject to copy-on- write updates.  This flag is only supported on file systems which perform copy-on-write.  (Note: For btrfs, the 'C' flag should be set on new or empty files.  If it is set on a file which already has data blocks, it is undefined when the blocks assigned to the file will be fully stable.  If the 'C' flag is set on a directory, it will have no effect on the directory, but new files created in that directory will have the No_COW attribute set. If the 'C' flag is set, then the 'c' flag cannot be set.)
d      A file with the 'd' attribute set is not a candidate for backup when the dump(8) program is run.
D      When a directory with the 'D' attribute set is modified, the changes are written synchronously to the disk; this is equivalent to the 'dirsync' mount option applied to a subset of the files.
e      The 'e' attribute indicates that the file is using extents for mapping the blocks on disk.  It may not be removed using chattr(1).
E      A file, directory, or symlink with the 'E' attribute set is encrypted by the file system.  This attribute may not be set or cleared using chattr(1), although it can be displayed by lsattr(1).
F      A directory with the 'F' attribute set indicates that all the path lookups inside that directory are made in a case-insensitive fashion.  This attribute can only be changed in empty directories on file systems with the casefold feature enabled.
i      A file with the 'i' attribute cannot be modified: it cannot be deleted or renamed, no link can be created to this file, most of the file's metadata can not be modified, and the file can not be opened in write mode.  Only the superuser or a process possessing the CAP_LINUX_IMMUTABLE capability can set or clear this attribute.
I      The 'I' attribute is used by the htree code to indicate that a directory is being indexed using hashed trees.  It may not be set or cleared using chattr(1), although it can be displayed by lsattr(1).
j      A file with the 'j' attribute has all of its data written to the ext3 or ext4 journal before being written to the file itself, if the file system is mounted with the "data=ordered" or "data=writeback" options and the file system has a journal.  When the file system is mounted with the "data=journal" option all file data is already journalled and this attribute has no effect.  Only the superuser or a process possessing the CAP_SYS_RESOURCE capability can set or clear this attribute.
m      A file with the 'm' attribute is excluded from compression on file systems that support per-file compression.
N      A file with the 'N' attribute set indicates that the file has data stored inline, within the inode itself. It may not be set or cleared using chattr(1), although it can be displayed by lsattr(1).
P      A directory with the 'P' attribute set will enforce a hierarchical structure for project id's.  This means that files and directories created in the directory will inherit the project id of the directory, rename operations are constrained so when a file or directory is moved into another directory, that the project ids must match.  In addition, a hard link to file can only be created when the project id for the file and the destination directory match.
s      When a file with the 's' attribute set is deleted, its blocks are zeroed and written back to the disk.  Note: please make sure to read the bugs and limitations section at the end of this document.
S      When a file with the 'S' attribute set is modified, the changes are written synchronously to the disk; this is equivalent to the 'sync' mount option applied to a subset of the files.
t      A file with the 't' attribute will not have a partial block fragment at the end of the file merged with other files (for those file systems which support tail-merging).  This is necessary for applications such as LILO which read the file system directly, and which don't understand tail-merged files.  Note: As of this writing, the ext2, ext3, and ext4 file systems do not support tail-merging.
T      A directory with the 'T' attribute will be deemed to be the top of directory hierarchies for the purposes of the Orlov block allocator.  This is a hint to the block allocator used by ext3 and ext4 that the subdirectories under this directory are not related, and thus should be spread apart for allocation purposes.   For example it is a very good idea to set the 'T' attribute on the /home directory, so that /home/john and /home/mary are placed into separate block groups.  For directories where this attribute is not set, the Orlov block allocator will try to group subdirectories closer together where possible.
u      When a file with the 'u' attribute set is deleted, its contents are saved.  This allows the user to ask for its undeletion.  Note: please make sure to read the bugs and limitations section at the end of this document.
x      The 'x' attribute can be set on a directory or file.  If the attribute is set on an existing directory, it will be inherited by all files and subdirectories that are subsequently created in the directory.  If an existing directory has contained some files and subdirectories, modifying the attribute on the parent directory doesn't change the attributes on these files and subdirectories.
V      A file with the 'V' attribute set has fs-verity enabled.  It cannot be written to, and the file system will automatically verify all data read from it against a cryptographic hash that covers the entire file's contents, e.g. via a Merkle tree.  This makes it possible to efficiently authenticate the file.  This attribute may not be set or cleared using chattr(1), although it can be displayed by lsattr(1).
chattr was written by Remy Card <Remy.Card@linux.org>.  It is currently being maintained by Theodore Ts'o <tytso@alum.mit.edu>.
The 'c', 's',  and 'u' attributes are not honored by the ext2, ext3, and ext4 file systems as implemented in the current mainline Linux kernels. Setting 'a' and 'i' attributes will not affect the ability to write to already existing file descriptors.
The 'j' option is only useful for ext3 and ext4 file systems.
The 'D' option is only useful on Linux kernel 2.5.19 and later.
chattr is part of the e2fsprogs package and is available from http://e2fsprogs.sourceforge.net.
lsattr(1), btrfs(5), ext4(5), xfs(5).
MOSQUITTO_SUB(1)                    Commands                    MOSQUITTO_SUB(1)
mosquitto_sub - an MQTT version 5/3.1.1/3.1 client for subscribing to topics
mosquitto_sub {[-h hostname] [--unix socket path] [-p port-number] [-u username] [-P password] -t message-topic... | -L URL [-t message-topic...] } [-A bind-address] [-c] [-C msg-count] [-d] [-D command identifier value] [-E] [-i client-id] [-I client-id-prefix] [-k keepalive-time] [-N] [--nodelay] [--pretty] [-q message-QoS] [--random-filter chance] [--remove-retained] [-R | --retained-only] [--retain-as-published] [-S] [-T filter-out...] [-U unsub-topic...] [-v] [-V protocol-version] [-W message-processing-timeout] [-x session-expiry-interval] [--proxy socks-url] [--quiet] [--will-topic topic [--will-payload payload] [--will-qos qos] [--will-retain]] [[{--cafile file | --capath dir} [--cert file] [--key file] [--tls-version version] [--tls-alpn protocol] [--tls-engine engine] [--keyform {pem | engine}] [--tls-engine-kpass-sha1 kpass-sha1] [--tls-use-os-certs] [--insecure]] | [--psk hex-key --psk-identity identity [--tls-version version]]]
mosquitto_sub [--help]
mosquitto_sub is a simple MQTT version 5/3.1.1 client that will subscribe to topics and print the messages that it receives.
In addition to subscribing to topics, mosquitto_sub can filter out received messages so they are not printed (see the -T option) or unsubscribe from topics (see the -U option). Unsubscribing from topics is useful for clients connecting with clean session set to false.
mosquitto_sub supports TLS encrypted connections. It is strongly recommended that you use an encrypted connection for anything more than the most basic setup.
To enable TLS connections when using x509 certificates, one of either --cafile or --capath can be provided as an option.
Alternatively, if the -p 8883 option is used then the OS provided certificates will be loaded and neither --cafile or --capath are needed
To enable TLS connections when using TLS-PSK, you must use the --psk and the --psk-identity options.
The options below may be given on the command line, but may also be placed in a config file located at $XDG_CONFIG_HOME/mosquitto_sub or $HOME/.config/mosquitto_sub with one pair of -option value per line. The values in the config file will be used as defaults and can be overridden by using the command line. The exceptions to this are -t and -T, which if given in the config file will not be overridden. Note also that currently some options cannot be negated, e.g.  -S. Config file lines that have a # as the first character are treated as comments and not processed any further.
-A Bind the outgoing connection to a local ip address/hostname. Use this argument if you need to restrict network communication to a particular interface.
-c, --disable-clean-session Disable 'clean session' / enable persistent client mode. When this argument is used, the broker will be instructed not to clean existing sessions for the same client id when the client connects, and sessions will never expire when the client disconnects. MQTT v5 clients can change their session expiry interval with the -x argument.
When a session is persisted on the broker, the subscriptions for the client will be maintained after it disconnects, along with subsequent QoS 1 and QoS 2 messages that arrive. When the client reconnects and does not clean the session, it will receive all of the queued messages.
If using this option, the client id must be set manually with --id
--cafile Define the path to a file containing PEM encoded CA certificates that are trusted. Used to enable SSL communication.
See also --capath
--capath Define the path to a directory containing PEM encoded CA certificates that are trusted. Used to enable SSL communication.
For --capath to work correctly, the certificate files must have ".crt" as the file ending and you must run "openssl rehash <path to capath>" each time you add/remove a certificate.
See also --cafile
--cert Define the path to a file containing a PEM encoded certificate for this client, if required by the server.
See also --key.
--ciphers An openssl compatible list of TLS ciphers to support in the client. See ciphers(1) for more information.
-C Disconnect and exit the program immediately after the given count of messages have been received. This may be useful in shell scripts where on a single status value is required, for example.
Combine with -R to print only the first set of fresh messages (i.e. that does not have the retained flag set), or with -T to filter which topics are processed.
-d, --debug Enable debug messages.
-D, --property Use an MQTT v5 property with this publish. If you use this option, the client will be set to be an MQTT v5 client. This option has two forms:
-D command identifier value
-D command identifier name value
command is the MQTT command/packet identifier and can be one of CONNECT, PUBACK, PUBREC, PUBCOMP, SUBSCRIBE, UNSUBSCRIBE, DISCONNECT, AUTH, or WILL. The properties available for each command are listed in the Properties section.
identifier is the name of the property to add. This is as described in the specification, but with '-' as a word separator. For example: payload-format-indicator. More details are in the Properties section.
value is the value of the property to add, with a data type that is property specific.
name is only used for the user-property property as the first of the two strings in the string pair. In that case, value is the second of the strings in the pair.
-E If this option is given, mosquitto_sub will exit immediately that all of its subscriptions have been acknowledged by the broker. In conjunction with -c this allows a durable client session to be initialised on the broker for future use without requiring any messages to be received.
-F Specify output printing format. This option allows you to choose what information from each message is printed to the screen. See the Output Format section below for full details.
This option overrides the -v option, but does not override the -N option.
--help Display usage information.
-h, --host Specify the host to connect to. Defaults to localhost.
-i, --id The id to use for this client. If not given, a client id will be generated depending on the MQTT version being used. For v3.1.1/v3.1, the client generates a client id in the format mosq-XXXXXXXXXXXXXXXXXX, where the X are replaced with random alphanumeric characters. For v5.0, the client sends a zero length client id, and the server will generate a client id for the client.
This option cannot be used at the same time as the --id-prefix argument.
-I, --id-prefix Provide a prefix that the client id will be built from by appending the process id of the client. This is useful where the broker is using the clientid_prefixes option. Cannot be used at the same time as the --id argument.
--insecure When using certificate based encryption, this option disables verification of the server hostname in the server certificate. This can be useful when testing initial server configurations but makes it possible for a malicious third party to impersonate your server through DNS spoofing, for example. Use this option in testing only. If you need to resort to using this option in a production environment, your setup is at fault and there is no point using encryption.
-k, --keepalive The number of seconds between sending PING commands to the broker for the purposes of informing it we are still connected and functioning. Defaults to 60 seconds.
--key Define the path to a file containing a PEM encoded private key for this client, if required by the server.
See also --cert.
--keyform Specifies the type of private key in use when making TLS connections.. This can be "pem" or "engine". This parameter is useful when a TPM module is being used and the private key has been created with it. Defaults to "pem", which means normal private key files are used.
See also --tls-engine.
-L, --url Specify specify user, password, hostname, port and topic at once as a URL. The URL must be in the form: mqtt(s)://[username[:password]@]host[:port]/topic
If the scheme is mqtt:// then the port defaults to 1883. If the scheme is mqtts:// then the port defaults to 8883.
-N Do not append an end of line character to the payload when printing. This allows streaming of payload data from multiple messages directly to another application unmodified. Only really makes sense when not using -v.
--nodelay Disable Nagle's algorithm for the socket. This means that latency of sent messages is reduced, which is particularly noticeable for small, reasonably infrequent messages. Using this option may result in more packets being sent than would normally be necessary.
-p, --port Connect to the port specified. If not given, the default of 1883 for plain MQTT or 8883 for MQTT over TLS will be used.
-P, --pw Provide a password to be used for authenticating with the broker. Using this argument without also specifying a username is invalid when using MQTT v3.1 or v3.1.1. See also the --username option.
--pretty When using the JSON output format %j or %J, the default is to print in an unformatted fashion. Specifying --pretty prints messages in a prettier, more human readable format.
--proxy Specify a SOCKS5 proxy to connect through. "None" and "username" authentication types are supported. The socks-url must be of the form socks5h://[username[:password]@]host[:port]. The protocol prefix socks5h means that hostnames are resolved by the proxy. The symbols %25, %3A and %40 are URL decoded into %, : and @ respectively, if present in the username or password.
If username is not given, then no authentication is attempted. If the port is not given, then the default of 1080 is used.
More SOCKS versions may be available in the future, depending on demand, and will use different protocol prefixes as described in curl(1).
--psk Provide the hexadecimal (no leading 0x) pre-shared-key matching the one used on the broker to use TLS-PSK encryption support. --psk-identity must also be provided to enable TLS-PSK.
--psk-identity The client identity to use with TLS-PSK support. This may be used instead of a username if the broker is configured to do so.
-q, --qos Specify the quality of service desired for the incoming messages, from 0, 1 and 2. Defaults to 0. See mqtt(7) for more information on QoS.
The QoS is identical for all topics subscribed to in a single instance of mosquitto_sub.
--quiet If this argument is given, no runtime errors will be printed. This excludes any error messages given in case of invalid user input (e.g. using --port without a port).
-R If this argument is given, messages that are received that have the retain bit set will not be printed. Messages with retain set are "stale", in that it is not known when they were originally published. When subscribing to a wildcard topic there may be a large number of retained messages. This argument suppresses their display.
--random-filter This option can be used to reduce the proportion of messages that mosquitto_sub prints. The default behaviour is to print all incoming messages. Setting the chance to a floating point value between 0.1 and 100.0 will ensure that on average that percentage of messages will be printed.
--remove-retained If this argument is given, the when mosquitto_sub receives a message with the retained bit set, it will send a message to the broker to clear that retained message. This applies to all received messages except those that are filtered out by the -T option. This option still takes effect even if -R is used. See also the --retain-as-published and --retained-only options.
Example 1.  Remove all retained messages on the server, assuming we have access to do so, and then exit:
mosquitto_sub -t '#' --remove-retained --retained-only
Example 2.  Remove a whole tree, with the exception of a single topic:
mosquitto_sub -t 'bbc/#' -T bbc/bbc1 --remove-retained
--retained-only If this argument is given, only messages that are received that have the retain bit set will be printed. Messages with retain set are "stale", in that it is not known when they were originally published. With this argument in use, the receipt of the first non-stale message will cause the client to exit. See also the --retain-as-published option.
--retain-as-published If this argument is given, the subscriptions will have the "retain as published" option set. This means that the retain flag on an incoming message will be exactly as set by the publishing client, rather than indicating whether the message is fresh/stale.
This option is not valid for MQTT v3.1/v3.1.1 clients.
-S Use SRV lookups to determine which host to connect to. Performs lookups to _mqtt._tcp.<host> when used in conjunction with -h, otherwise uses _mqtt._tcp.<local dns domain>.
-t, --topic The MQTT topic to subscribe to. See mqtt(7) for more information on MQTT topics.
This option may be repeated to subscribe to multiple topics.
-T, --filter-out Suppress printing of topics that match the filter. This allows subscribing to a wildcard topic and only printing a partial set of the wildcard hierarchy.
For example, subscribe to the BBC tree, but suppress output from Radio 3:
•   mosquitto_sub -t bbc/# -T bbc/radio3
This option may be repeated to filter out multiple topics or topic trees.
--tls-alpn Provide a protocol to use when connecting to a broker that has multiple protocols available on a single port, e.g. MQTT and WebSockets.
--tls-engine A valid openssl engine id. These can be listed with openssl engine command.
See also --keyform.
--tls-engine-kpass-sha1 SHA1 of the private key password when using an TLS engine. Some TLS engines such as the TPM engine may require the use of a password in order to be accessed. This option allows a hex encoded SHA1 hash of the password to the engine directly, instead of the user being prompted for the password.
--tls-use-os-certs If used, this will load and trust the OS provided CA certificates. This can be used in conjunction with --cafile and --capath and can be used on its own to enable TLS mode. This will be set by default if -L mqtts://...  is used, or if port is 8883 and no other certificate options are used.
--tls-version Choose which TLS protocol version to use when communicating with the broker. Valid options are tlsv1.3, tlsv1.2 and tlsv1.1. The default value is tlsv1.2. Must match the protocol version used by the broker.
-u, --username Provide a username to be used for authenticating with the broker. See also the --pw argument.
--unix Connect to a broker through a local unix domain socket instead of a TCP socket. This is a replacement for -h and -L. For example: mosquitto_pub --unix /tmp/mosquitto.sock ...
See the socket_domain option in mosquitto.conf(5) to configure Mosquitto to listen on a unix socket.
-U, --unsubscribe A topic that will be unsubscribed from. This may be used on its own or in conjunction with the --topic option and only makes sense when used in conjunction with --clean-session.
If used with --topic then subscriptions will be processed before unsubscriptions.
Note that it is only possible to unsubscribe from subscriptions that have previously been made. It is not possible to punch holes in wildcard subscriptions. For example, subscribing to sensors/# and then unsubscribing from sensors/+/temperature as shown below will still result in messages matching the sensors/+/temperature being delivered to the client.
•   mosquitto_sub -t sensors/# -U sensors/+/temperature -v
Note also that because retained messages are published by the broker on receipt of a SUBSCRIBE command, subscribing and unsubscribing to the same topic may result in messages being received at the client.
This option may be repeated to unsubscribe from multiple topics.
-v, --verbose Print received messages verbosely. With this argument, messages will be printed as "topic payload". When this argument is not given, the messages are printed as "payload".
-V, --protocol-version Specify which version of the MQTT protocol should be used when connecting to the remote broker. Can be 5, 311, 31, or the more verbose mqttv5, mqttv311, or mqttv31. Defaults to 311.
-W Provide a timeout as an integer number of seconds. mosquitto_sub will stop processing messages and disconnect after this number of seconds has passed. The timeout starts just after the client has connected to the broker.
--will-payload Specify a message that will be stored by the broker and sent out if this client disconnects unexpectedly. This must be used in conjunction with --will-topic.
--will-qos The QoS to use for the Will. Defaults to 0. This must be used in conjunction with --will-topic.
--will-retain If given, if the client disconnects unexpectedly the message sent out will be treated as a retained message. This must be used in conjunction with --will-topic.
--will-topic The topic on which to send a Will, in the event that the client disconnects unexpectedly.
-x Set the session-expiry-interval property on the CONNECT packet. Applies to MQTT v5 clients only. Set to 0-4294967294 to specify the session will expire in that many seconds after the client disconnects, or use -1, 4294967295, or ∞ for a session that does not expire. Defaults to -1 if -c is also given, or 0 if -c not given.
If the session is set to never expire, either with -x or -c, then a client id must be provided.
There are three ways of formatting the output from mosquitto_sub. In all cases a new-line character is appended for each message received unless the -N argument is passed to mosquitto_sub.
Payload-only is the default output format and will print the payload exactly as it is received.
Verbose mode is activated with -v and prints the message topic and the payload, separated by a space.
The final option is formatted output, which allows the user to define a custom output format. The behaviour is controlled with the -F format-string option. The format string is a free text string where interpreted sequences are replaced by different parameters. The available interpreted sequences are described below.
Three characters are used to start an interpreted sequence: %, @ and \. Sequences starting with % are either parameters related to the MQTT message being printed, or are helper sequences to avoid the need to type long date format strings for example. Sequences starting with @ are passed to the strftime(3) function (with the @ replaced with a % - note that only the character immediately after the @ is passed to strftime). This allows the construction of a wide variety of time based outputs. The output options for strftime vary from platform to platform, so please check what is available for your platform. mosquitto_sub does provide one extension to strftime which is @N, which can be used to obtain the number of nanoseconds passed in the current second. The resolution of this option varies depending on the platform. The final sequence character is \, which is used to input some characters that would otherwise be difficult to enter.
Flag characters The parameters %A, %C, %E, %F, %I, %l, %m, %p, %R, %S, %t, %x, and %X can have optional flags immediately after the % character.
0 The value should be zero padded. This applies to the parameters %A, %E, %F, %l, %m, %S, %X, and %x. It will be ignored for other parameters. If used with the - flag, the 0 flag will be ignored.
- The value will be left aligned to the field width, padded with blanks. The default is right alignment, with either 0 or blank padding.
Field width Some of the MQTT related parameters can be formatted with an option to set their field width in a similar way to regular printf style formats, i.e. this sets the minimum width when printing this parameter. This applies to the options %A, %C, %E, %F, %I, %l, %m, %p, %R, %S, %t, %x, %X.
For example %10t would set the minimum topic field width to 10 characters.
Maximum width Some of the MQTT related parameters can be formatted with an option to set a maximum field width in a similar way to regular printf style formats. This applies to the options %C, %I, %R, %t.
For example %10.10t would set the minimum topic field width to 10 characters, and the maximum topic width to 10 characters, i.e. the field will always be exactly 10 characters long.
MQTT related parameters •   %% a literal %.
•   %A the MQTT v5 topic-alias property, if present.
•   %C the MQTT v5 content-type property, if present.
•   %D the MQTT v5 correlation-data property, if present. Note that this property is specified as binary data, so may produce non-printable characters.
•   %E the MQTT v5 message-expiry-interval property, if present.
•   %F the MQTT v5 payload-format-indicator property, if present.
•   %l the length of the payload in bytes.
•   %m the message id (only relevant for messages with QoS>0).
•   %P the MQTT v5 user-property property, if present. This will be printed in the form key:value. It is possible for any number of user properties to be attached to a message, and to have duplicate keys.
•   %p the payload raw bytes (may produce non-printable characters depending on the payload).
•   %q the message QoS.
•   %R the MQTT v5 response-topic property, if present.
•   %r the retained flag for the message.
•   %S the MQTT v5 subscription-identifier property, if present.
•   %t the message topic.
•   %x the payload with each byte as a hexadecimal number (lower case).
•   %X the payload with each byte as a hexadecimal number (upper case).
Helpers •   %I ISO-8601 format date and time, e.g. 2016-08-10T09:47:38+0100
•   %j JSON output of message parameters and timestamp, with a quoted and escaped payload. For example {"tst":"2020-05-06T22:12:00.000000+0100","topic":"greeting","qos":0,"retain":0,"payload":"hello world"}
•   %J JSON output of message parameters and timestamp, with a non-quoted and non-escaped payload - this means the payload must itself be valid JSON. For example: {"tst":"2020-05-06T22:12:00.000000+0100","topic":"foo","qos":0,"retain":0,"payload":{"temperature":27.0,"humidity":57}}.
If the payload is not valid JSON, then the error message "Error: Message payload is not valid JSON on topic <topic>" will be printed to stderr.
•   %I ISO-8601 format date and time, e.g. 2016-08-10T09:47:38+0100
•   %U Unix timestamp with nanoseconds, e.g. 1470818943.786368637
Time related parameters •   @@ a literal @.
•   @X pass the character represented by X to the strftime function as %X. The options supported are platform dependent.
•   @N the number of nanoseconds that have passed in the current second, with varying timing resolution depending on platform.
Escape characters •   \\ a literal \.
•   \0 a null character. Can be used to separate different parameters that may contain spaces (e.g. topic, payload) so that processing with tools such as xargs(1) is easier.
•   \a alert/bell.
•   \e the escape sequence, which can be used with ANSI colour codes to provide coloured output for example.
•   \n end of line.
•   \r carriage return.
•   \t horizontal tab.
•   \v vertical tab.
mosquitto_sub can register a message with the broker that will be sent out if it disconnects unexpectedly. See mqtt(7) for more information.
The minimum requirement for this is to use --will-topic to specify which topic the will should be sent out on. This will result in a non-retained, zero length message with QoS 0.
Use the --will-retain, --will-payload and --will-qos arguments to modify the other will parameters.
The -D / --property option allows adding properties to different stages of the mosquitto_sub run. The properties supported for each command are as follows:
Connect •   authentication-data (binary data - note treated as a string in mosquitto_sub)
•   authentication-method (UTF-8 string)
•   maximum-packet-size (32-bit unsigned integer)
•   receive-maximum (16-bit unsigned integer)
•   request-problem-information (8-bit unsigned integer)
•   request-response-information (8-bit unsigned integer)
•   session-expiry-interval (32-bit unsigned integer, note use -x instead)
•   topic-alias-maximum (16-bit unsigned integer)
•   user-property (UTF-8 string pair)
Subscribe •   user-property (UTF-8 string pair)
Unsubscribe •   user-property (UTF-8 string pair)
Disconnect •   session-expiry-interval (32-bit unsigned integer)
Will properties •   content-type (UTF-8 string)
•   correlation-data (binary data - note treated as a string in mosquitto_sub)
•   message-expiry-interval (32-bit unsigned integer)
•   payload-format-indicator (8-bit unsigned integer)
•   response-topic (UTF-8 string)
•   will-delay-interval (32-bit unsigned integer)
Note that these really are examples - the subscriptions will work if you run them as shown, but there must be something publishing messages on those topics for you to receive anything.
Subscribe to temperature information on localhost with QoS 1:
•   mosquitto_sub -t sensors/temperature -q 1
Subscribe to hard drive temperature updates on multiple machines/hard drives. This expects each machine to be publishing its hard drive temperature to sensors/machines/HOSTNAME/temperature/HD_NAME.
•   mosquitto_sub -t sensors/machines/+/temperature/+
Subscribe to all broker status messages:
•   mosquitto_sub -v -t \$SYS/#
Specify the output format as "ISO-8601 date : topic : payload in hex"
•   mosquitto_sub -F '@Y-@m-@dT@H:@M:@S@z : %t : %x' -t '#'
Specify the output format as "seconds since epoch.nanoseconds : retained flag : qos : mid : payload length"
•   mosquitto_sub -F '%@s.@N : %r : %q : %m : %l' -q 2 -t '#'
Topic and payload output, but with colour where supported.
•   mosquitto_sub -F '\e[92m%t \e[96m%p\e[0m' -q 2 -t '#'
0 Success
27 Timed out waiting for message
Other non-zero value Unspecified failure
$XDG_CONFIG_HOME/mosquitto_sub, $HOME/.config/mosquitto_sub Configuration file for default options.
mqtt(7), mosquitto_pub(1), mosquitto_rr(1), mosquitto(8), libmosquitto(3), mosquitto-tls(7)
scrot(1)               command line screen capture utility              scrot(1)
scrot - command line screen capture utility
scrot [-bcfhikmopsuvz] [-a X,Y,W,H] [-C NAME] [-D DISPLAY] [-d SEC] [-e CMD] [-F FILE] [-l STYLE] [-n OPTS] [-q NUM] [-S CMD] [-t NUM | GEOM] [FILE]
scrot (SCReenshOT) is a simple command line screen capture utility, it uses imlib2 to grab and save images.
scrot has many useful features:
•  Support for multiple image formats: JPG, PNG, GIF, and others.
•  The screenshot's quality is configurable.
•  It is possible to capture a specific window or a rectangular area on the screen.
Because scrot is a command line utility, it can easily be scripted and put to novel uses. For instance, scrot can be used to monitor an X server in absence.
scrot is free software under the MIT-advertising license.
-a, --autoselect X,Y,W,H Non-interactively choose a rectangle starting at position X,Y and of W by H resolution.
-b, --border When selecting a window, grab the WM's border too.  Use with -s to raise the focus of the window.
-C, --class NAME NAME is a window class name. Associative with -k.
-c, --count Display a countdown when used with -d.
-D, --display DISPLAY DISPLAY is the display to use; see X(7).
-d, --delay SEC Wait SEC seconds before taking a shot.
-e, --exec CMD Execute CMD on the saved image.
-F, --file File name. See SPECIAL STRINGS.
-f, --freeze Freeze the screen when -s is used.
-h, --help Display help and exit.
-i, --ignorekeyboard Don't exit for keyboard input. ESC still exits.
-k, --stack OPT Capture stack/overlapped windows and join them. A running Composite Manager is needed. OPT it's optional join letter: v/h (vertical/horizontal). Default: h
-l, --line STYLE STYLE indicates the style of the line when the -s option is used; see SELECTION STYLE.
-m, --multidisp For multiple heads, screenshot all of them in order.
-n, --note OPTS OPTS is a collection of options which specify notes to bake into the image. See NOTE FORMAT.
-o, --overwrite By default scrot does not overwrite the output FILE, use this option to enable it.
-p, --pointer Capture the mouse pointer.
-q, --quality NUM NUM must be between 1 and 100. For lossless output formats, a higher value represents better but slower compression. For lossy output formats, a higher value represents higher quality and larger file size. Default: 75.
-S, --script CMD CMD is an imlib2 script.
-s, --select OPT Interactively select a window or rectangle with the mouse, use the arrow keys to resize. See the -l and -f options. OPT it's optional; see SELECTION MODE
-t, --thumb NUM | GEOM Also generate a thumbnail. The argument is the resolution of the thumbnail, it may be a percentage NUM or a resolution GEOM. Examples: 10, 25, 320x240, 500x200.
-u, --focused Use the currently focused window.
-v, --version Output version information and exit.
-z, --silent Prevent beeping.
-      Redirection to standard output. The output image format is PNG.
-e, -F and FILE parameters can take format specifiers that are expanded by scrot when encountered. There are two types of format specifier: Characters preceded by a '%' are interpreted by strftime(2). The second kind are internal to scrot and are prefixed by '$'. The following specifiers are recognised by scrot:
$$   A literal '$'. $a   The system's hostname. $f   The image's full path (ignored when used in the filename). $h   The image's height. $m   The thumbnail's full path (ignored when used in the filename). $n   The image's basename (ignored when used in the filename). $p   The image's pixel size. $s   The image's size in bytes (ignored when used in the filename). $t   The image's file format (ignored when used in the filename). $w   The image's width. \n   A literal newline (ignored when used in the filename).
$ scrot '%Y-%m-%d_$wx$h.png' -e 'optipng $f'
This would create a PNG file with a name similar to 2000-10-30_2560x1024.png and optimize it with optipng(1).
When using -s, optionally you can indicate the action to perform with the selection area.  Some actions allow optional parameters too.
capture             Capture the selection area, this action is by default and does not need to be specified.
hole                Highlight the selected area overshadowing the rest of the capture.
hide,IMAGE          Hide the selection area by drawing an area of color (or image) over it. Optionally indicate name of the image to use as cover. Image has priority over color.
blur,AMOUNT         Blurs the selection area. Optionally you can specify the amount of blur. Amount,range: 1..30,  default: 18
In modes 'hole' and 'hide' the color of the area is indicated by 'color' property of the line style and the opacity of the color (or image) is indicated by property 'opacity', SELECTION STYLE
If the 'hide' mode uses an image that does not have an alpha channel, the opacity parameter will be ignored and it will be drawn fully opaque.
$ scrot --select=hide $ scrot -shole --line color="Dark Salmon",opacity=200 $ scrot -sblur,10 $ scrot -shide,stamp.png --line opacity=120
When using -s, you can indicate the style of the line with -l.
-l takes a comma-separated list of specifiers as argument:
style=STYLE     STYLE is either "solid" or "dash" without quotes.
width=NUM       NUM is a pixel count between 1 and 8 inclusive.
color="COLOR"   Color is a hexadecimal HTML color code or the name of a color. HTML color codes are composed of a pound sign '#' followed by a sequence of 3 2-digit hexadecimal numbers which represent red, green, and blue respectively. Examples: #FF0000 (red), #E0FFFF (light cyan), #000000 (black).
opacity=NUM     NUM is between 0 and 255 inclusive. 255 means 100% opaque, 0 means 100% transparent. For the opacity of the line this is only effective if a Composite Manager is running.
mode=MODE       MODE is either "edge" or "classic" without quotes. edge is the new selection, classic uses the old one. "edge" ignores the style specifier and the -f flag, "classic" ignores the opacity specifier.
Without the -l option, a default style is used:
mode=classic,style=solid,width=1,opacity=100
$ scrot -l style=dash,width=3,color="red" -s
The -n option's argument is more arguments:
-f  'FontName/size' -t  'text' -x  position (optional) -y  position (optional) -c  color(RGBA, range 0..255) (optional) -a  angle (optional)
$ scrot -n "-f '/usr/share/fonts/TTF/DroidSans-Bold/40' -x 10 -y 20 -c 255,0,0,255 -t 'Hi'"
scrot was originally developed by Tom Gilbert.
Currently, source code is maintained by volunteers. Newer versions are available at https://github.com/resurrecting-open-source-projects/scrot
st-util(1)                           stlink                           st-util(1)
st-util - Run GDB server to interact with STM32 device
st-util [<ARGS>...]
Start a GDB server to interact with a STM32 device Run the main binary of the local package (src/main.rs).
If a port number is not specified using the –listen_port option, the default 4242 port will be used.
Stlink version 2 is used by default unless the option –stlinkv1 is given.
The STLinkV2 device to use can be specified in the environment variable STLINK_DEVICE on the format :.
-h, --help Print this message.
-v XX, --verbose=XX Specify a specific verbosity level (0..99)
-v, --verbose Specify generally verbose logging
-s X, --stlink_version=X Choose what version of stlink to use, (defaults to 2)
-1, --stlinkv1 Force stlink version 1
-p 4242, --listen_port=1234 Set the gdb server listen port.  (default port: 4242)