neulab/tldr huggingface dataset:
Specify a dithering algorithm with the optional method argument. The default, ‘floyd-steinberg’, uses Floyd-Steinberg error diffusion. This usually looks best, but can cause animation artifacts, because dithering choices will vary from frame to frame. Gifsicle also supports ordered dithering algorithms that avoid animation artifacts.  The ‘ro64’ mode uses a large, random-looking pattern and generally produces good results. The ‘o3’, ‘o4’, and ‘o8’ modes use smaller, more regular patterns. The ‘ordered’ mode chooses a good ordered dithering algorithm. For special effects, try the halftone modes ‘halftone’, ‘squarehalftone’, and ‘diagonal’. Some modes take optional parameters using commas. The halftone modes take a cell size and a color limit: ‘halftone,10,3’ creates 10-pixel wide halftone cells where each cell uses up to 3 colors.
--gamma gamma Set the gamma correction to gamma, which can be a real number or ‘srgb’.  Roughly speaking, higher numbers exaggerate shadows and lower numbers exaggerate highlights.  The default is the function defined by the standard sRGB color space, which usually works well. (Its effects are similar to --gamma=2.2.) Gifsicle uses gamma correction when choosing a color palette (--colors) and when dithering (--dither).
--lossy[=lossiness] Alter image colors to shrink output file size at the cost of artifacts and noise.  Lossiness determines how many artifacts are allowed; higher values can result in smaller file sizes, but cause more artifacts. The default lossiness is 20.
--change-color color1 color2 Change color1 to color2 in the following input GIFs. (The color arguments have the same forms as in the -t option.) Change multiple colors by giving the option multiple times. Color changes don't interfere with one another, so you can safely swap two colors with ‘--change-color color1 color2 --change-color color2 color1’.  They all take effect as an input GIF is read.  --no-change-color cancels all color changes.
--transform-colormap command Command should be a shell command that reads from standard input and writes to standard output. Each colormap in the output GIF is translated into text colormap format (see --use-colormap below) and piped to the command. The output that command generates (which should also be in text colormap format) will replace the input colormap. The replacement doesn't consider color matching, so pixels that used color slot n in the input will still use color slot n in the output.
--use-colormap colormap Change the image to use colormap.  Each pixel in the image is changed to the closest match in colormap (or, if --dither is on, to a dithered combination of colors in colormap).  Colormap can be web for the 216-color “Web-safe palette”; gray for grayscale; bw for black-and-white; or the name of a file. That file should either be a text file (the format is described below) or a GIF file, whose global colormap will be used. If --colors=N is also given, an N-sized subset of colormap will be used.
Text colormap files use this format:
First, let's create an animation, ‘anim.gif’:
gifsicle a.gif b.gif c.gif d.gif > anim.gif
This animation will move very quickly: since we didn't specify a delay, a browser will cycle through the frames as fast as it can. Let's slow it down and pause .5 seconds between frames, using the --delay option.
gifsicle --delay 50 a.gif b.gif c.gif d.gif > anim.gif
If we also want the GIF to loop three times, we can use --loopcount:
gifsicle -d 50 --loop=3 a.gif b.gif c.gif d.gif > anim.gif
(Rather than type --delay again, we used its short form, -d.  Many options have short forms; you can see them by running ‘gifsicle --help’. We also abbreviated --loopcount to --loop, which is OK since no other option starts with ‘loop’.)
To explode ‘anim.gif’ into its component frames:
gifsicle --explode anim.gif ls anim.gif* anim.gif  anim.gif.000  anim.gif.001  anim.gif.002  anim.gif.003
To optimize ‘anim.gif’:
gifsicle -b -O2 anim.gif
To change the second frame of ‘anim.gif’ to ‘x.gif’:
gifsicle -b --unoptimize -O2 anim.gif --replace "#1" x.gif
--unoptimize is used since ‘anim.gif’ was optimized in the last step. Editing individual frames in optimized GIFs is dangerous without --unoptimize; frames following the changed frame could be corrupted by the change.  Of course, this might be what you want.
Note that --unoptimize and --optimize can be on simultaneously. --unoptimize affects input GIF files, while --optimize affects output GIF files.
To print information about the first and fourth frames of ‘anim.gif’:
gifsicle -I "#0" "#3" < anim.gif
To make black the transparent color in all the GIFs in the current directory, and also print information about each:
gifsicle -bII --trans "#000000" *.gif
Giving -I twice forces normal output to occur. With only one -I, the GIFs would not be modified.
To change ‘anim.gif’ to use a 64-color subset of the Web-safe palette:
gifsicle -b --colors=64 --use-col=web anim.gif
To make a dithered black-and-white version of ‘anim.gif’:
gifsicle --dither --use-col=bw anim.gif > anim-bw.gif
To overlay one GIF atop another -- producing a one-frame output GIF that looks like the superposition of the two inputs -- use gifsicle twice:
gifsicle bottom.gif top.gif | gifsicle -U "#1" > result.gif
Some optimized output GIFs may appear incorrectly on some GIF implementations (for example, Java's); see the --careful option.
Please email suggestions, additions, patches and bugs to ekohler@gmail.com.
For a tutorial on GIF images and animations, you might try some of the resources listed on-line at webreference.com: http://www.webreference.com/authoring/graphics/animation.html
Eddie Kohler <ekohler@gmail.com> http://www.read.seas.harvard.edu/~kohler/ He wrote it.
Anne Dudfield <annied@frii.com> http://www.frii.com/~annied/ She named it.
Hans Dinsen-Hansen <dino@danbbs.dk> http://www.danbbs.dk/~dino/ Adaptive tree method for GIF writing.
Kornel Lesinski --lossy option.
http://www.lcdf.org/gifsicle/ The gifsicle home page.
NGREP(8)                          User Manuals                          NGREP(8)
ngrep - network grep
ngrep <-hNXViwqpevxlDtTRM> <-IO pcap_dump > < -n num > < -d dev > < -A num > < -s snaplen > < -S limitlen > < -W normal|byline|single|none > < -c cols > < -P char > < -F file > < match expression > < bpf filter >
ngrep strives to provide most of GNU grep's common features, applying them to the network layer.  ngrep is a pcap-aware tool that will allow you to specify extended regular expressions to match against data payloads of packets.  It currently recognizes TCP, UDP and ICMP across Ethernet, PPP, SLIP, FDDI and null interfaces, and understands bpf filter logic in the same fashion as more common packet sniffing tools, such as tcpdump(8) and snoop(1).
-h     Display help/usage information.
-N     Show sub-protocol number along with single-character identifier (useful when observing raw or unknown protocols).
-X     Treat the match expression as a hexadecimal string.  See the explanation of match expression below.
-i     Ignore case for the regex expression.
-w     Match the regex expression as a word.
-q     Be quiet; don't output any information other than packet headers and their payloads (if relevant).
-p     Don't put the interface into promiscuous mode.
-e     Show empty packets.  Normally empty packets are discarded because they have no payload to search.  If specified, empty packets will be shown, regardless of the specified regex expression.
-v     Invert the match; only display packets that don't match.
-x     Dump packet contents as hexadecimal as well as ASCII.
-l     Make stdout line buffered.
-D     When reading pcap_dump files, replay them at their recorded time intervals (mimic realtime).
-t     Print a timestamp in the form of YYYY/MM/DD HH:MM:SS.UUUUUU everytime a packet is matched.
-T     Print a timestamp in the form of +S.UUUUUU, indicating the delta between packet matches.  Specify a second time to indicate the delta since the first packet match.
-R     Do not try to drop privileges to the DROPPRIVS_USER.
ngrep makes no effort to validate input from live or offline sources as it is focused more on performance and handling large amounts of data than protocol correctness, which is most often a fair assumption to make.  However, sometimes it matters and thus as a rule ngrep will try to be defensive and drop any root privileges it might have.
There exist scenarios where this behaviour can become an obstacle, so this option is provided to end-users who want to disable this feature, but must do so with an understanding of the risks. Packets can be randomly malformed or even specifically designed to overflow sniffers and take control of them, and revoking root privileges is currently the only risk mitigation ngrep employs against such an attack.  Use this option and turn it off at your own risk.
-c cols Explicitly set the console width to ``cols''.  Note that this is the console width, and not the full width of what ngrep prints out as payloads; depending on the output mode ngrep may print less than ``cols'' bytes per line (indentation).
-F file Read in the bpf filter from the specified filename.  This is a compatibility option for users familiar with tcpdump.  Please note that specifying ``-F'' will override any bpf filter specified on the command-line.
-P char Specify an alternate character to signify non-printable characters when displayed.  The default is ``.''.
-K num Kill matching TCP connections (like tcpkill).  The numeric argument controls how many RST segments are sent.
-W normal|byline|single|none Specify an alternate manner for displaying packets, when not in hexadecimal mode.  The ``byline'' mode honors embedded linefeeds, wrapping text only when a linefeed is encountered (useful for observing HTTP transactions, for instance).  The ``none'' mode doesn't wrap under any circumstance (entire payload is displayed on one line).  The ``single'' mode is conceptually the same as ``none'', except that everything including IP and source/destination header information is all on one line. ``normal'' is the default mode and is only included for completeness.  This option is incompatible with ``-x''.
-s snaplen Set the bpf caplen to snaplen (default 65536).
-S limitlen Set the upper limit on the size of packets that ngrep will look at.  Useful for looking at only the first N bytes of packets without changing the BPF snaplen.
-I pcap_dump Input file pcap_dump into ngrep.  Works with any pcap-compatible dump file format.  This option is useful for searching for a wide range of different patterns over the same packet stream.
-O pcap_dump Output matched packets to a pcap-compatible dump file.  This feature does not interfere with normal output to stdout.
-n num Match only num packets total, then exit.
-d dev By default ngrep will select a default interface to listen on. Use this option to force ngrep to listen on interface dev.
-A num Dump num packets of trailing context after matching a packet.
match expression A match expression is either an extended regular expression, or if the -X option is specified, a string signifying a hexadecimal value.  An extended regular expression follows the rules as implemented by the GNU regex library.  Hexadecimal expressions can optionally be preceded by `0x'.  E.g., `DEADBEEF', `0xDEADBEEF'.
bpf filter Selects a filter that specifies what packets will be dumped.  If no bpf filter is given, all IP packets seen on the selected interface will be dumped.  Otherwise, only packets for which bpf filter is `true' will be dumped.
The bpf filter consists of one or more primitives.  Primitives usually consist of an id (name or number) preceded by one or more qualifiers. There are three different kinds of qualifier:
type   qualifiers say what kind of thing the id name or number refers to. Possible types are host, net and port.  E.g., `host blort', `net 1.2.3', `port 80'.  If there is no type qualifier, host is assumed.
dir    qualifiers specify a particular transfer direction to and/or from id.  Possible directions are src, dst, src or dst and src and dst. E.g., `src foo', `dst net 1.2.3', `src or dst port ftp-data'.  If there is no dir qualifier, src or dst is assumed.  For `null' link layers (i.e. point to point protocols such as slip) the inbound and outbound qualifiers can be used to specify a desired direction.
proto  qualifiers are restricted to ip-only protocols.  Possible protos are: tcp , udp and icmp.  e.g., `udp src foo' or `tcp port 21'. If there is no proto qualifier, all protocols consistent with the type are assumed.  E.g., `src foo' means `ip and ((tcp or udp) src foo)', `net bar' means `ip and (net bar)', and `port 53' means `ip and ((tcp or udp) port 53)'.
In addition to the above, there are some special `primitive' keywords that don't follow the pattern: gateway, broadcast, less, greater and arithmetic expressions.  All of these are described below.
More complex filter expressions are built up by using the words and, or and not to combine primitives.  E.g., `host blort and not port ftp and not port ftp-data'.  To save typing, identical qualifier lists can be omitted.  E.g., `tcp dst port ftp or ftp-data or domain' is exactly the same as `tcp dst port ftp or tcp dst port ftp-data or tcp dst port domain'.
Allowable primitives are:
dst host host True if the IP destination field of the packet is host, which may be either an address or a name.
src host host True if the IP source field of the packet is host.
host host True if either the IP source or destination of the packet is host. Any of the above host expressions can be prepended with the keywords, ip, arp, or rarp as in: ip host host which is equivalent to:
ether dst ehost True if the ethernet destination address is ehost.  Ehost may be either a name from /etc/ethers or a number (see ethers(3N) for numeric format).
ether src ehost True if the ethernet source address is ehost.
ether host ehost True if either the ethernet source or destination address is ehost.
gateway host True if the packet used host as a gateway.  I.e., the ethernet source or destination address was host but neither the IP source nor the IP destination was host.  Host must be a name and must be found in both /etc/hosts and /etc/ethers.  (An equivalent expression is ether host ehost and not host host which can be used with either names or numbers for host / ehost.)
dst net net True if the IP destination address of the packet has a network number of net. Net may be either a name from /etc/networks or a network number (see networks(4) for details).
src net net True if the IP source address of the packet has a network number of net.
net net True if either the IP source or destination address of the packet has a network number of net.
net net mask mask True if the IP address matches net with the specific netmask.  May be qualified with src or dst.
net net/len True if the IP address matches net a netmask len bits wide.  May be qualified with src or dst.
dst port port True if the packet is ip/tcp or ip/udp and has a destination port value of port.  The port can be a number or a name used in /etc/services (see tcp(4P) and udp(4P)).  If a name is used, both the port number and protocol are checked.  If a number or ambiguous name is used, only the port number is checked (e.g., dst port 513 will print both tcp/login traffic and udp/who traffic, and port domain will print both tcp/domain and udp/domain traffic).
src port port True if the packet has a source port value of port.
port port True if either the source or destination port of the packet is port.  Any of the above port expressions can be prepended with the keywords, tcp or udp, as in: tcp src port port which matches only tcp packets whose source port is port.
less length True if the packet has a length less than or equal to length. This is equivalent to: len <= length.
greater length True if the packet has a length greater than or equal to length. This is equivalent to: len >= length.
ip proto protocol True if the packet is an ip packet (see ip(4P)) of protocol type protocol.  Protocol can be a number or one of the names tcp, udp or icmp.  Note that the identifiers tcp and udp are also keywords and must be escaped via backslash (\), which is \\ in the C-shell.
ip broadcast True if the packet is an IP broadcast packet.  It checks for both the all-zeroes and all-ones broadcast conventions, and looks up the local subnet mask.
ip multicast True if the packet is an IP multicast packet.
ip     Abbreviation for: ether proto ip
tcp, udp, icmp Abbreviations for: ip proto p where p is one of the above protocols.
expr relop expr True if the relation holds, where relop is one of >, <, >=, <=, =, !=, and expr is an arithmetic expression composed of integer constants (expressed in standard C syntax), the normal binary operators [+, -, *, /, &, |], a length operator, and special packet data accessors.  To access data inside the packet, use the following syntax: proto [ expr : size ] Proto is one of ip, tcp, udp or icmp, and indicates the protocol layer for the index operation.  The byte offset, relative to the indicated protocol layer, is given by expr.  Size is optional and indicates the number of bytes in the field of interest; it can be either one, two, or four, and defaults to one.  The length operator, indicated by the keyword len, gives the length of the packet.
For example, `ether[0] & 1 != 0' catches all multicast traffic. The expression `ip[0] & 0xf != 5' catches all IP packets with options. The expression `ip[6:2] & 0x1fff = 0' catches only unfragmented datagrams and frag zero of fragmented datagrams. This check is implicitly applied to the tcp and udp index operations.  For instance, tcp[0] always means the first byte of the TCP header, and never means the first byte of an intervening fragment.
Primitives may be combined using:
A parenthesized group of primitives and operators (parentheses are special to the Shell and must be escaped).
Negation (`!' or `not').
Concatenation (`&&' or `and').
Alternation (`||' or `or').
Negation has highest precedence.  Alternation and concatenation have equal precedence and associate left to right.  Note that explicit and tokens, not juxtaposition, are now required for concatenation.
If an identifier is given without a keyword, the most recent keyword is assumed.  For example, not host vs and ace is short for not host vs and host ace which should not be confused with not ( host vs or ace )
Expression arguments can be passed to ngrep as either a single argument or as multiple arguments, whichever is more convenient.  Generally, if the expression contains Shell metacharacters, it is easier to pass it as a single, quoted argument.  Multiple arguments are concatenated with spaces before being parsed.
Errors from ngrep, libpcap, and the GNU regex library are all output to stderr.
The ngrep utility exits with one of the following values:
0     One or more frames were matched. 1     No frames were matched. 2     An error occurred. 3+    Hell is freezing over, run!
Written by Jordan Ritter <jpr5@darkridge.com>.
Please report bugs to the ngrep's GitHub Issue Tracker, located at
http://github.com/jpr5/ngrep/issues
Non-bug, non-feature-request general feedback should be sent to the author directly by email.
ALL YOUR BASE ARE BELONG TO US.
DOCKERD(8)                     Docker User Manuals                    DOCKERD(8)
dockerd - Enable daemon mode
dockerd [--add-runtime[=[]]] [--allow-nondistributable-artifacts[=[]]] [--api-cors-header=[=API-CORS-HEADER]] [--authorization-plugin[=[]]] [-b|--bridge[=BRIDGE]] [--bip[=BIP]] [--cgroup-parent[=[]]] [--cluster- store[=[]]] [--cluster-advertise[=[]]] [--cluster-store-opt[=map[]]] [--config-file[=/etc/docker/daemon.json]] [--containerd[=SOCKET-PATH]] [--data-root[=/var/lib/docker]] [-D|--debug] [--default-cgroupns- mode[=host]] [--default-gateway[=DEFAULT-GATEWAY]] [--default-gateway- v6[=DEFAULT-GATEWAY-V6]] [--default-address-pool[=DEFAULT-ADDRESS-POOL]] [--default-runtime[=runc]] [--default-ipc-mode=MODE] [--default-shm- size[=64MiB]] [--default-ulimit[=[]]] [--dns[=[]]] [--dns-opt[=[]]] [--dns-search[=[]]] [--exec-opt[=[]]] [--exec-root[=/var/run/docker]] [--experimental[=false]] [--fixed-cidr[=FIXED-CIDR]] [--fixed-cidr- v6[=FIXED-CIDR-V6]] [-G|--group[=docker]] [-H|--host[=[]]] [--help] [--icc[=true]] [--init[=false]] [--init-path[=""]] [--insecure- registry[=[]]] [--ip[=0.0.0.0]] [--ip-forward[=true]] [--ip-masq[=true]] [--iptables[=true]] [--ipv6] [--isolation[=default]] [-l|--log- level[=info]] [--label[=[]]] [--live-restore[=false]] [--log- driver[=json-file]] [--log-opt[=map[]]] [--mtu[=0]] [--max-concurrent- downloads[=3]] [--max-concurrent-uploads[=5]] [--max-download- attempts[=5]] [--node-generic-resources[=[]]] [-p|--pidfile[=/var/run/docker.pid]] [--raw-logs] [--registry- mirror[=[]]] [-s|--storage-driver[=STORAGE-DRIVER]] [--seccomp- profile[=SECCOMP-PROFILE-PATH]] [--selinux-enabled] [--shutdown- timeout[=15]] [--storage-opt[=[]]] [--swarm-default-advertise- addr[=IP|INTERFACE]] [--tls] [--tlscacert[=~/.docker/ca.pem]] [--tlscert[=~/.docker/cert.pem]] [--tlskey[=~/.docker/key.pem]] [--tlsverify] [--userland-proxy[=true]] [--userland-proxy-path[=""]] [--userns-remap[=default]]
dockerd is used for starting the Docker daemon (i.e., to command the daemon to manage images, containers etc).  So dockerd is a server, as a daemon.
To run the Docker daemon you can specify dockerd.  You can check the daemon options using dockerd --help.  Daemon options should be specified after the dockerd keyword in the following format.
dockerd [OPTIONS]
--add-runtime=[] Runtimes can be registered with the daemon either via the configuration file or using the --add-runtime command line argument.
The following is an example adding 2 runtimes via the configuration:
{ "default-runtime": "runc", "runtimes": { "runc": { "path": "runc" }, "custom": { "path": "/usr/local/bin/my-runc-replacement", "runtimeArgs": [ "--debug" ] } } }
This is the same example via the command line:
$ sudo dockerd --add-runtime runc=runc --add-runtime custom=/usr/local/bin/my-runc-replacement
Note: defining runtime arguments via the command line is not supported.
--allow-nondistributable-artifacts=[] Push nondistributable artifacts to the specified registries.
List can contain elements with CIDR notation to specify a whole subnet.
This option is useful when pushing images containing nondistributable artifacts to a registry on an air-gapped network so hosts on that network can pull the images without connecting to another server.
Warning: Nondistributable artifacts typically have restrictions on how and where they can be distributed and shared. Only use this feature to push artifacts to private registries and ensure that you are in compliance with any terms that cover redistributing nondistributable artifacts.
--api-cors-header="" Set CORS headers in the Engine API. Default is cors disabled. Give urls like "http://foo, http://bar, ...". Give "*" to allow all.
--authorization-plugin="" Set authorization plugins to load
-b, --bridge="" Attach containers to a pre-existing network bridge; use 'none' to disable container networking
--bip="" Use the provided CIDR notation address for the dynamically created bridge (docker0); Mutually exclusive of -b
--cgroup-parent="" Set parent cgroup for all containers. Default is "/docker" for fs cgroup driver and "system.slice" for systemd cgroup driver.
--cluster-store="" URL of the distributed storage backend
--cluster-advertise="" Specifies the 'host:port' or interface:port combination that this particular daemon instance should use when advertising itself to the cluster. The daemon is reached through this value.
--cluster-store-opt="" Specifies options for the Key/Value store.
--config-file="/etc/docker/daemon.json" Specifies the JSON file path to load the configuration from.
--containerd="" Path to containerd socket.
--data-root="" Path to the directory used to store persisted Docker data such as configuration for resources, swarm cluster state, and filesystem data for images, containers, and local volumes. Default is /var/lib/docker.
-D, --debug=true|false Enable debug mode. Default is false.
--default-cgroupns-mode="host|private" Set the default cgroup namespace mode for newly created containers. The argument can either be host or private. If unset, this defaults to host on cgroup v1, private on cgroup v2.
--default-gateway="" IPv4 address of the container default gateway; this address must be part of the bridge subnet (which is defined by -b or --bip)
--default-gateway-v6="" IPv6 address of the container default gateway
--default-address-pool="" Default address pool from which IPAM driver selects a subnet for the networks. Example: base=172.30.0.0/16,size=24 will set the default address pools for the selected scope networks to {172.30.[0-255].0/24}
--default-runtime="runc" Set default runtime if there're more than one specified by --add- runtime.
--default-ipc-mode="private|shareable" Set the default IPC mode for newly created containers. The argument can either be private or shareable.
--default-shm-size=64MiB Set the daemon-wide default shm size for containers. Default is 64MiB.
--default-ulimit=[] Default ulimits for containers.
--dns="" Force Docker to use specific DNS servers
--dns-opt="" DNS options to use.
--dns-search=[] DNS search domains to use.
--exec-opt=[] Set runtime execution options. See RUNTIME EXECUTION OPTIONS.
--exec-root="" Path to use as the root of the Docker execution state files. Default is /var/run/docker.
--experimental="" Enable the daemon experimental features.
--fixed-cidr="" IPv4 subnet for fixed IPs (e.g., 10.20.0.0/16); this subnet must be nested in the bridge subnet (which is defined by -b or --bip).
--fixed-cidr-v6="" IPv6 subnet for global IPv6 addresses (e.g., 2a00:1450::/64)
-G, --group="" Group to assign the unix socket specified by -H when running in daemon mode. use '' (the empty string) to disable setting of a group. Default is docker.
-H, --host=[unix:///var/run/docker.sock]: tcp://[host:port] to bind or unix://[/path/to/socket] to use. The socket(s) to bind to in daemon mode specified using one or more tcp://host:port, unix:///path/to/socket, fd://* or fd://socketfd.
--help Print usage statement
--icc=true|false Allow unrestricted inter-container and Docker daemon host communication. If disabled, containers can still be linked together using the --link option (see docker-run(1)). Default is true.
--init Run an init process inside containers for signal forwarding and process reaping.
--init-path Path to the docker-init binary.
--insecure-registry=[] Enable insecure registry communication, i.e., enable un-encrypted and/or untrusted communication.
List of insecure registries can contain an element with CIDR notation to specify a whole subnet. Insecure registries accept HTTP and/or accept HTTPS with certificates from unknown CAs.
Enabling --insecure-registry is useful when running a local registry. However, because its use creates security vulnerabilities it should ONLY be enabled for testing purposes.  For increased security, users should add their CA to their system's list of trusted CAs instead of using --insecure-registry.
--ip="" Default IP address to use when binding container ports. Default is 0.0.0.0.
--ip-forward=true|false Enables IP forwarding on the Docker host. The default is true. This flag interacts with the IP forwarding setting on your host system's kernel. If your system has IP forwarding disabled, this setting enables it. If your system has IP forwarding enabled, setting this flag to --ip- forward=false has no effect.
This setting will also enable IPv6 forwarding if you have both --ip-forward=true and --fixed-cidr-v6 set. Note that this may reject Router Advertisements and interfere with the host's existing IPv6 configuration. For more information, please consult the documentation about "Advanced Networking - IPv6".
--ip-masq=true|false Enable IP masquerading for bridge's IP range. Default is true.
--iptables=true|false Enable Docker's addition of iptables rules. Default is true.
--ipv6=true|false Enable IPv6 support. Default is false. Docker will create an IPv6-enabled bridge with address fe80::1 which will allow you to create IPv6-enabled containers. Use together with --fixed-cidr-v6 to provide globally routable IPv6 addresses. IPv6 forwarding will be enabled if not used with --ip-forward=false. This may collide with your host's current IPv6 settings. For more information please consult the documentation about "Advanced Networking - IPv6".
--isolation="default" Isolation specifies the type of isolation technology used by containers. Note that the default on Windows server is process, and the default on Windows client is hyperv. Linux only supports default.
-l, --log-level="debug|info|warn|error|fatal" Set the logging level. Default is info.
--label="[]" Set key=value labels to the daemon (displayed in docker info)
--live-restore=false Enable live restore of running containers when the daemon starts so that they are not restarted. This option is applicable only for docker daemon running on Linux host.
--log-driver="json- file|syslog|journald|gelf|fluentd|awslogs|splunk|etwlogs|gcplogs|none" Default driver for container logs. Default is json-file. Warning: docker logs command works only for json-file logging driver.
--log-opt=[] Logging driver specific options.
--mtu=0 Set the containers network mtu. Default is 0.
--max-concurrent-downloads=3 Set the max concurrent downloads for each pull. Default is 3.
--max-concurrent-uploads=5 Set the max concurrent uploads for each push. Default is 5.
--max-download-attempts=5 Set the max download attempts for each pull. Default is 5.
--node-generic-resources=[] Advertise user-defined resource. Default is []. Use this if your swarm cluster has some nodes with custom resources (e.g: NVIDIA GPU, SSD, ...) and you need your services to land on nodes advertising these resources. Usage example: --node-generic-resources "NVIDIA-GPU=UUID1" --node-generic-resources "NVIDIA-GPU=UUID2"
-p, --pidfile="" Path to use for daemon PID file. Default is /var/run/docker.pid
--raw-logs Output daemon logs in full timestamp format without ANSI coloring. If this flag is not set, the daemon outputs condensed, colorized logs if a terminal is detected, or full ("raw") output otherwise.
--registry-mirror=:// Prepend a registry mirror to be used for image pulls. May be specified multiple times.
-s, --storage-driver="" Force the Docker runtime to use a specific storage driver.
--seccomp-profile="" Path to seccomp profile.
--selinux-enabled=true|false Enable selinux support. Default is false.
--shutdown-timeout=15 Set the shutdown timeout value in seconds. Default is 15.
--storage-opt=[] Set storage driver options. See STORAGE DRIVER OPTIONS.
--swarm-default-advertise-addr=IP|INTERFACE Set default address or interface for swarm to advertise as its externally-reachable address to other cluster members. This can be a hostname, an IP address, or an interface such as eth0. A port cannot be specified with this option.
--tls=true|false Use TLS; implied by --tlsverify. Default is false.
--tlscacert=~/.docker/ca.pem Trust certs signed only by this CA.
--tlscert=~/.docker/cert.pem Path to TLS certificate file.
--tlskey=~/.docker/key.pem Path to TLS key file.
--tlsverify=true|false Use TLS and verify the remote (daemon: verify client, client: verify daemon). Default is false.
--userland-proxy=true|false Rely on a userland proxy implementation for inter-container and outside-to-container loopback communications. Default is true.
--userland-proxy-path="" Path to the userland proxy binary.
--userns-remap=default|uid:gid|user:group|user|uid Enable user namespaces for containers on the daemon. Specifying "default" will cause a new user and group to be created to handle UID and GID range remapping for the user namespace mappings used for contained processes. Specifying a user (or uid) and optionally a group (or gid) will cause the daemon to lookup the user and group's subordinate ID ranges for use as the user namespace mappings for contained processes.
Docker uses storage backends (known as "graphdrivers" in the Docker internals) to create writable containers from images.  Many of these backends use operating system level technologies and can be configured.
Specify options to the storage backend with --storage-opt flags. The backends that currently take options are devicemapper, zfs and btrfs. Options for devicemapper are prefixed with dm, options for zfs start with zfs and options for btrfs start with btrfs.
Specifically for devicemapper, the default is a "loopback" model which requires no pre-configuration, but is extremely inefficient.  Do not use it in production.
To make the best use of Docker with the devicemapper backend, you must have a recent version of LVM.  Use lvm to create a thin pool; for more information see man lvmthin.  Then, use --storage-opt dm.thinpooldev to tell the Docker engine to use that pool for allocating images and container snapshots.
Devicemapper options dm.thinpooldev Specifies a custom block storage device to use for the thin pool.
If using a block device for device mapper storage, it is best to use lvm to create and manage the thin-pool volume. This volume is then handed to Docker to exclusively create snapshot volumes needed for images and containers.
Managing the thin-pool outside of Engine makes for the most feature-rich method of having Docker utilize device mapper thin provisioning as the backing storage for Docker containers. The highlights of the lvm-based thin-pool management feature include: automatic or interactive thin-pool resize support, dynamically changing thin-pool features, automatic thinp metadata checking when lvm activates the thin-pool, etc.
As a fallback if no thin pool is provided, loopback files are created. Loopback is very slow, but can be used without any pre-configuration of storage. It is strongly recommended that you do not use loopback in production. Ensure your Engine daemon has a --storage-opt dm.thinpooldev argument provided.
Example use:
$ dockerd \ --storage-opt dm.thinpooldev=/dev/mapper/thin-pool
dm.directlvm_device As an alternative to manually creating a thin pool as above, Docker can automatically configure a block device for you.
$ dockerd \ --storage-opt dm.directlvm_device=/dev/xvdf
dm.thinp_percent Sets the percentage of passed in block device to use for storage.
Example: $ sudo dockerd \ --storage-opt dm.thinp_percent=95
dm.thinp_metapercent Sets the percentage of the passed in block device to use for metadata storage.
Example: $ sudo dockerd \ --storage-opt dm.thinp_metapercent=1
dm.thinp_autoextend_threshold Sets the value of the percentage of space used before lvm attempts to autoextend the available space [100 = disabled]
Example: $ sudo dockerd \ --storage-opt dm.thinp_autoextend_threshold=80
dm.thinp_autoextend_percent Sets the value percentage value to increase the thin pool by when lvm attempts to autoextend the available space [100 = disabled]
Example: $ sudo dockerd \ --storage-opt dm.thinp_autoextend_percent=20
dm.basesize Specifies the size to use when creating the base device, which limits the size of images and containers. The default value is 10G. Note, thin devices are inherently "sparse", so a 10G device which is mostly empty doesn't use 10 GB of space on the pool. However, the filesystem will use more space for base images the larger the device is.
The base device size can be increased at daemon restart which will allow all future images and containers (based on those new images) to be of the new base device size.
Example use: dockerd --storage-opt dm.basesize=50G
This will increase the base device size to 50G. The Docker daemon will throw an error if existing base device size is larger than 50G. A user can use this option to expand the base device size however shrinking is not permitted.
This value affects the system-wide "base" empty filesystem that may already be initialized and inherited by pulled images. Typically, a change to this value requires additional steps to take effect:
$ sudo service docker stop $ sudo rm -rf /var/lib/docker $ sudo service docker start
Example use: dockerd --storage-opt dm.basesize=20G
dm.fs Specifies the filesystem type to use for the base device. The supported options are ext4 and xfs. The default is ext4.
Example use: dockerd --storage-opt dm.fs=xfs
dm.mkfsarg Specifies extra mkfs arguments to be used when creating the base device.
Example use: dockerd --storage-opt "dm.mkfsarg=-O ^has_journal"
dm.mountopt Specifies extra mount options used when mounting the thin devices.
Example use: dockerd --storage-opt dm.mountopt=nodiscard
dm.use_deferred_removal Enables use of deferred device removal if libdm and the kernel driver support the mechanism.
Deferred device removal means that if device is busy when devices are being removed/deactivated, then a deferred removal is scheduled on device. And devices automatically go away when last user of the device exits.
For example, when a container exits, its associated thin device is removed. If that device has leaked into some other mount namespace and can't be removed, the container exit still succeeds and this option causes the system to schedule the device for deferred removal. It does not wait in a loop trying to remove a busy device.
Example use: dockerd --storage-opt dm.use_deferred_removal=true
dm.use_deferred_deletion Enables use of deferred device deletion for thin pool devices. By default, thin pool device deletion is synchronous. Before a container is deleted, the Docker daemon removes any associated devices. If the storage driver can not remove a device, the container deletion fails and daemon returns.
Error deleting container: Error response from daemon: Cannot destroy container
To avoid this failure, enable both deferred device deletion and deferred device removal on the daemon.
dockerd --storage-opt dm.use_deferred_deletion=true --storage-opt dm.use_deferred_removal=true
With these two options enabled, if a device is busy when the driver is deleting a container, the driver marks the device as deleted. Later, when the device isn't in use, the driver deletes it.
In general it should be safe to enable this option by default. It will help when unintentional leaking of mount point happens across multiple mount namespaces.
dm.loopdatasize Note: This option configures devicemapper loopback, which should not be used in production.
Specifies the size to use when creating the loopback file for the "data" device which is used for the thin pool. The default size is 100G. The file is sparse, so it will not initially take up this much space.
Example use: dockerd --storage-opt dm.loopdatasize=200G
dm.loopmetadatasize Note: This option configures devicemapper loopback, which should not be used in production.
Specifies the size to use when creating the loopback file for the "metadata" device which is used for the thin pool. The default size is 2G. The file is sparse, so it will not initially take up this much space.
Example use: dockerd --storage-opt dm.loopmetadatasize=4G
dm.datadev (Deprecated, use dm.thinpooldev)
Specifies a custom blockdevice to use for data for a Docker-managed thin pool.  It is better to use dm.thinpooldev - see the documentation for it above for discussion of the advantages.
dm.metadatadev (Deprecated, use dm.thinpooldev)
Specifies a custom blockdevice to use for metadata for a Docker-managed thin pool.  See dm.datadev for why this is deprecated.
dm.blocksize Specifies a custom blocksize to use for the thin pool.  The default blocksize is 64K.
Example use: dockerd --storage-opt dm.blocksize=512K
dm.blkdiscard Enables or disables the use of blkdiscard when removing devicemapper devices.  This is disabled by default due to the additional latency, but as a special case with loopback devices it will be enabled, in order to re-sparsify the loopback file on image/container removal.
Disabling this on loopback can lead to much faster container removal times, but it also prevents the space used in /var/lib/docker directory from being returned to the system for other use when containers are removed.
Example use: dockerd --storage-opt dm.blkdiscard=false
dm.override_udev_sync_check By default, the devicemapper backend attempts to synchronize with the udev device manager for the Linux kernel.  This option allows disabling that synchronization, to continue even though the configuration may be buggy.
To view the udev sync support of a Docker daemon that is using the devicemapper driver, run:
$ docker info [...] Udev Sync Supported: true [...]
When udev sync support is true, then devicemapper and udev can coordinate the activation and deactivation of devices for containers.
When udev sync support is false, a race condition occurs between the devicemapper and udev during create and cleanup. The race condition results in errors and failures. (For information on these failures, see docker#4036 ⟨https://github.com/docker/docker/issues/4036⟩)
To allow the docker daemon to start, regardless of whether udev sync is false, set dm.override_udev_sync_check to true:
$ dockerd --storage-opt dm.override_udev_sync_check=true
When this value is true, the driver continues and simply warns you the errors are happening.
Note: The ideal is to pursue a docker daemon and environment that does support synchronizing with udev. For further discussion on this topic, see docker#4036 ⟨https://github.com/docker/docker/issues/4036⟩. Otherwise, set this flag for migrating existing Docker daemons to a daemon with a supported environment.
dm.min_free_space Specifies the min free space percent in a thin pool require for new device creation to succeed. This check applies to both free data space as well as free metadata space. Valid values are from 0% - 99%. Value 0% disables free space checking logic. If user does not specify a value for this option, the Engine uses a default value of 10%.
Whenever a new a thin pool device is created (during docker pull or during container creation), the Engine checks if the minimum free space is available.  If the space is unavailable, then device creation fails and any relevant docker operation fails.
To recover from this error, you must create more free space in the thin pool to recover from the error. You can create free space by deleting some images and containers from tge thin pool. You can also add more storage to the thin pool.
To add more space to an LVM (logical volume management) thin pool, just add more storage to the  group container thin pool; this should automatically resolve any errors. If your configuration uses loop devices, then stop the Engine daemon, grow the size of loop files and restart the daemon to resolve the issue.
Example use:: dockerd --storage-opt dm.min_free_space=10%
dm.xfs_nospace_max_retries Specifies the maximum number of retries XFS should attempt to complete IO when ENOSPC (no space) error is returned by underlying storage device.
By default XFS retries infinitely for IO to finish and this can result in unkillable process. To change this behavior one can set xfs_nospace_max_retries to say 0 and XFS will not retry IO after getting ENOSPC and will shutdown filesystem.
$ sudo dockerd --storage-opt dm.xfs_nospace_max_retries=0
dm.libdm_log_level Specifies the maxmimum libdm log level that will be forwarded to the dockerd log (as specified by --log-level). This option is primarily intended for debugging problems involving libdm. Using values other than the defaults may cause false-positive warnings to be logged.
Values specified must fall within the range of valid libdm log levels. At the time of writing, the following is the list of libdm log levels as well as their corresponding levels when output by dockerd.
┌────────────┬───────┬─────────────┐ │libdm Level │ Value │ --log-level │ ├────────────┼───────┼─────────────┤ │_LOG_FATAL  │ 2     │ error       │ ├────────────┼───────┼─────────────┤ │_LOG_ERR    │ 3     │ error       │ ├────────────┼───────┼─────────────┤ │_LOG_WARN   │ 4     │ warn        │ ├────────────┼───────┼─────────────┤ │_LOG_NOTICE │ 5     │ info        │ ├────────────┼───────┼─────────────┤ │_LOG_INFO   │ 6     │ info        │ ├────────────┼───────┼─────────────┤ │_LOG_DEBUG  │ 7     │ debug       │ └────────────┴───────┴─────────────┘
$ sudo dockerd \ --log-level debug \ --storage-opt dm.libdm_log_level=7
ZFS options zfs.fsname Set zfs filesystem under which docker will create its own datasets.  By default docker will pick up the zfs filesystem where docker graph (/var/lib/docker) is located.
Example use: dockerd -s zfs --storage-opt zfs.fsname=zroot/docker
Btrfs options btrfs.min_space Specifies the minimum size to use when creating the subvolume which is used for containers. If user uses disk quota for btrfs when creating or running a container with --storage-opt size option, docker should ensure the size cannot be smaller than btrfs.min_space.
Example use: docker daemon -s btrfs --storage-opt btrfs.min_space=10G
The daemon uses libkv to advertise the node within the cluster.  Some Key/Value backends support mutual TLS, and the client TLS settings used by the daemon can be configured using the --cluster-store-opt flag, specifying the paths to PEM encoded files.
kv.cacertfile Specifies the path to a local file with PEM encoded CA certificates to trust
kv.certfile Specifies the path to a local file with a PEM encoded certificate.  This certificate is used as the client cert for communication with the Key/Value store.
kv.keyfile Specifies the path to a local file with a PEM encoded private key.  This private key is used as the client key for communication with the Key/Value store.
Access authorization Docker's access authorization can be extended by authorization plugins that your organization can purchase or build themselves. You can install one or more authorization plugins when you start the Docker daemon using the --authorization-plugin=PLUGIN_ID option.
dockerd --authorization-plugin=plugin1 --authorization-plugin=plugin2,...
The PLUGIN_ID value is either the plugin's name or a path to its specification file. The plugin's implementation determines whether you can specify a name or path. Consult with your Docker administrator to get information about the plugins available to you.
Once a plugin is installed, requests made to the daemon through the command line or Docker's Engine API are allowed or denied by the plugin. If you have multiple plugins installed, each plugin, in order, must allow the request for it to complete.
For information about how to create an authorization plugin, see access authorization plugin ⟨https://docs.docker.com/engine/extend/plugins_authorization/⟩ section in the Docker extend section of this documentation.
You can configure the runtime using options specified with the --exec-opt flag.  All the flag's options have the native prefix. A single native.cgroupdriver option is available.
The native.cgroupdriver option specifies the management of the container's cgroups. You can only specify cgroupfs or systemd. If you specify systemd and it is not available, the system errors out. If you omit the native.cgroupdriver option,cgroupfs is used on cgroup v1 hosts, systemd is used on cgroup v2 hosts with systemd available.
This example sets the cgroupdriver to systemd:
$ sudo dockerd --exec-opt native.cgroupdriver=systemd
Setting this option applies to all containers the daemon launches.
Sept 2015, Originally compiled by Shishir Mahajan shishir.mahajan@redhat.com ⟨mailto:shishir.mahajan@redhat.com⟩ based on docker.com source material and internal work.
CAL(1)                            User Commands                           CAL(1)
cal - display a calendar
cal [options] [[[day] month] year]
cal [options] [timestamp|monthname]
cal displays a simple calendar. If no arguments are specified, the current month is displayed.
The month may be specified as a number (1-12), as a month name or as an abbreviated month name according to the current locales.
Two different calendar systems are used, Gregorian and Julian. These are nearly identical systems with Gregorian making a small adjustment to the frequency of leap years; this facilitates improved synchronization with solar events like the equinoxes. The Gregorian calendar reform was introduced in 1582, but its adoption continued up to 1923. By default cal uses the adoption date of 3 Sept 1752. From that date forward the Gregorian calendar is displayed; previous dates use the Julian calendar system. 11 days were removed at the time of adoption to bring the calendar in sync with solar events. So Sept 1752 has a mix of Julian and Gregorian dates by which the 2nd is followed by the 14th (the 3rd through the 13th are absent).
Optionally, either the proleptic Gregorian calendar or the Julian calendar may be used exclusively. See --reform below.
-1, --one Display single month output. (This is the default.)