neulab/tldr huggingface dataset:
On Linux/Unix, in order to backup directories you must use tar : - to backup a directory  : tar cf - directory | 7za a -si directory.tar.7z - to restore your backup : 7za x -so directory.tar.7z | tar xf -
If you want to send files and directories (not the owner of file) to others Unix/MacOS/Windows users, you can use the 7-zip format.
example : 7za a directory.7z  directory
Do not use "-r" because this flag does not do what you think.
Do not use directory/* because of ".*" files (example : "directory/*" does not match "directory/.profile")
EXAMPLE 1 7za a -t7z -m0=lzma -mx=9 -mfb=64 -md=32m -ms=on archive.7z dir1 adds all files from directory "dir1" to archive archive.7z using "ultra settings"
-t7z   7z archive
-m0=lzma lzma method
-mx=9  level of compression = 9 (Ultra)
-mfb=64 number of fast bytes for LZMA = 64
-md=32m dictionary size = 32 megabytes
-ms=on solid archive = on
EXAMPLE 2 7za a -sfx archive.exe dir1 add all files from directory "dir1" to SFX archive archive.exe (Remark : SFX archive MUST end with ".exe")
EXAMPLE 3 7za a -mhe=on -pmy_password archive.7z a_directory add all files from directory "a_directory" to the archive "archive.7z" (with data and header archive encryption on)
7z(1), 7zr(1), bzip2(1), gzip(1), lzip(1), zip(1)
HTML Documentation /usr/share/doc/p7zip/DOC/MANUAL/index.htm
Written for Debian by Mohammed Adnene Trojette.
WMCTRL(1)                    General Commands Manual                   WMCTRL(1)
wmctrl - interact with a EWMH/NetWM compatible X Window Manager.
wmctrl [ options | actions ]...
wmctrl is a command that can be used to interact with an X Window manager that is compatible with the EWMH/NetWM specification.  wmctrl can query the window manager for information, and it can request that certain window management actions be taken.
wmctrl is controlled entirely by its command line arguments. The command line arguments are used to specify the action to be performed (with options that modify behavior) and any arguments that might be needed to perform the actions.
The following sections define the supported actions and options. Arguments to the actions and options are written in the form <ARGNAME> in the descriptions below. The detailed syntax for writing arguments are in a single section dedicated to that purpose.
The following command line arguments can be specified to invoke a wmctrl action. Only one action can be executed with the invocation of the wmctrl command.
-a <WIN> Switch to the desktop containing the window <WIN>, raise the window, and give it focus.
-b  ( add | remove | toggle),prop1 [,prop2 ] Add, remove, or toggle up to two window properties simultaneously. The window that is being modified must be identified with a -r action. The property change is achived by using the EWMH _NET_WM_STATE request. The supported property names (for prop1 and prop2) are modal, sticky, maximized_vert, maximized_horz, shaded, skip_taskbar, skip_pager, hidden, fullscreen, above and below. Two properties are supported to allow operations like maximizing a window to full screen mode. Note that this action is made up of exactly two shell command line arguments.
-c <WIN> Close the window <WIN> gracefully.
-d     List all desktops managed by the window manager. One line is output for each desktop, with the line broken up into space separated columns. The first column contains an integer desktop number. The second column contains a '*' character for the current desktop, otherwise it contains a '-' character. The next two columns contain the fixed string DG: and then the desktop geometry as '<width>x<height>' (e.g. '1280x1024'). The following two columns contain the fixed string VP: and then the viewport position in the format '<y>,<y>' (e.g. '0,0'). The next three columns after this contains the fixed string WA: and then two columns with the workarea geometry as 'X,Y and WxH' (e.g. '0,0 1280x998'). The rest of the line contains the name of the desktop (possibly containing multiple spaces).
-e <MVARG> Resize and move a window that has been specified with a -r action according to the <MVARG> argument.
-g w,h Change the geometry (common size) of all desktops so they are w pixels wide and h pixels high. w and h must be positive integers. A window manager may ignore this request.
-h     Print help text about program usage.
-I name Set the icon name (short title) of the window specified by a -r action to name.
-k  ( on  |  off  ) Turn on or off the window manager's "show the desktop" mode (if the window manager implements this feature).
-l     List the windows being managed by the window manager. One line is output for each window, with the line broken up into space separated columns.  The first column always contains the window identity as a hexadecimal integer, and the second column always contains the desktop number (a -1 is used to identify a sticky window). If the -p option is specified the next column will contain the PID for the window as a decimal integer. If the -G option is specified then four integer columns will follow: x- offset, y-offset, width and height. The next column always contains the client machine name. The remainder of the line contains the window title (possibly with multiple spaces in the title).
-m     Display information about the window manager and the environment.
-n N   Change the number of desktops to N (a non-negative integer).
-N name Set the name (long title) of the window specified by a -r action to name.
-o x,y Change the viewport for the current desktop. The values x and y are numeric offsets that specify the position of the top left corner of the viewport. A window manager may ignore this request.
-r <WIN> Specify a target window for an action.
-R <WIN> Move the window <WIN> to the current desktop, raise the window, and give it focus.
-s <DESK> Switch to the desktop <DESK>.
-t <DESK> Move a window that has been specified with the -r action to the desktop <DESK>.
-T name Set the both the name (long title) and icon name (short title) of the window specified by a -r action to name.  This action is like using the -N and -I actions at the same time (which would otherwise be impossible since wmctrl can execute only one action at a time).
The following options modify the default actions, or they modify the interpretation of arguments.
-F     Window name arguments (<WIN>) are to be treated as exact window titles that are case sensitive. Without this options window titles are considered to be case insensitive substrings of the full window title.
-G     Include geometry information in the output of the -l action.
-i     Interpret window arguments (<WIN>) as a numeric value rather than a string name for the window. If the numeric value starts with the prefix '0x' it is assumed to be a hexadecimal number.
-p     Include PIDs in the window list printed by the -l action. Prints a PID of '0' if the application owning the window does not support it.
-u     Override auto-detection and force UTF-8 mode.
-v     Provide verbose output. This is really useful when debugging wmctrl itself.
-w [ <WORKAROUND>[,<WORKAROUND>]... ] Use workarounds specified in the argument.
-x     Include WM_CLASS in the window list or interpret <WIN> as the WM_CLASS name.
<DESK> A Desktop is always specified by an integer which represents the desktop numbers. Desktop numbers start at 0.
<MVARG> A move and resize argument has the format 'g,x,y,w,h'.  All five components are integers. The first value, g, is the gravity of the window, with 0 being the most common value (the default value for the window). Please see the EWMH specification for other values.
The four remaining values are a standard geometry specification: x,y is the position of the top left corner of the window, and w,h is the width and height of the window, with the exception that the value of -1 in any position is interpreted to mean that the current geometry value should not be modified.
<WIN>  This argument specifies a window that is the target of an action. By default the argument is treated as if were a string, and windows are examined until one is found with a title the contains the specified string as a substring. The substring matching is done in a case insensitive manner. The -F option may be used to force exact, case sensitive title matching. The option -i may be used to interpret the window target as a numeric window identity instead of a string.
The window name string :SELECT: is treated specially. If this window name is used then wmctrl waits for the user to select the target window by clicking on it.
The window name string :ACTIVE: may be used to instruct wmctrl to use the currently active window for the action.
<WORKAROUND> There is only one work around currently implemeted. It is specified by using the string DESKTOP_TITLES_INVALID_UTF8 and it causes the printing of non-ASCII desktop tiles correctly when using Window Maker.
Getting a list of windows managed by the window manager
wmctrl -l
Getting a list of windows with PID and geometry information.
wmctrl -p -G -l
Going to the window with a name containing 'emacs' in it
wmctrl -a emacs
Shade a window with a title that contains the word 'mozilla'
wmctrl -r mozilla -b add,shaded
Close a very specifically titled window sticky
wmctrl -F -c 'Debian bug tracking system - Mozilla'
Toggle the 'stickiness' of a window with a specific window identity
wmctrl -i -r 0x0120002 -b add,sticky
Change the title of window to a specified string but choose the window by clicking on it
wmctrl -r :SELECT: -T "Selected Window"
zenity(1) is a useful dialog program for building scripts with wmctrl.
Some examples of EWMH/NetWM compatible window managers include recent versions of Enlightenment, Icewm, Kwin, Sawfish and Xfce.
wmctrl was written by Tomas Styblo <tripie@cpan.org>.
This manual page was written by Shyamal Prasad <shyamal@member.fsf.org> for the Debian project (but may be used by others).
java(1)                      General Commands Manual                     java(1)
Name java - the Java application launcher
java [ options ] class [ argument ... ] java [ options ] -jar file.jar [ argument ... ]
options Command-line options. See Options.
class The name of the class to be called.
file.jar The name of the JAR file to be called. Used only with the -jar command.
argument The arguments passed to the main function.
The java command starts a Java application. It does this by starting a Java runtime environment, loading a specified class, and calling that class's main method.
The method must be declared public and static, it must not return any value, and it must accept a String array as a parameter. The method declaration has the following form:
By default, the first argument without an option is the name of the class to be called. A fully qualified class name should be used. If the -jar option is specified, then the first non-option argument is the name of a JAR file containing class and resource files for the application, with the startup class indicated by the Main-Class manifest header.
The Java runtime searches for the startup class, and other classes used, in three sets of locations: the bootstrap class path, the installed extensions, and the user class path.
Non-option arguments after the class name or JAR file name are passed to the main function.
The launcher has a set of standard options that are supported in the current runtime environment.
In addition, the current implementations of the virtual machines support a set of nonstandard options that are subject to change in future releases. See Nonstandard Options.
Standard Options -client Selects the Java HotSpot Client VM. A 64-bit capable JDK currently ignores this option and instead uses the Java Hotspot Server VM. For default Java VM selection, see Server-Class Machine Detection at http://docs.oracle.com/javase/7/docs/technotes/guides/vm/server-class.html
-server Selects the Java HotSpot Server VM. On a 64-bit capable JDK, only the Java Hotspot Server VM is supported so the -server option is implicit. For default a Java VM selection, see Server-Class Machine Detection at http://docs.oracle.com/javase/7/docs/technotes/guides/vm/server-class.html
-agentlib:libname[=options] Loads native agent library libname, for example: -agentlib:hprof
-agentlib:jdwp=help
-agentlib:hprof=help See JVMTI Agent Command-Line Options at http://docs.oracle.com/javase/7/docs/platform/jvmti/jvmti.html#starting
-agentpath:pathname[=options] Loads a native agent library by full pathname. See JVMTI Command-Line Options at http://docs.oracle.com/javase/7/docs/platform/jvmti/jvmti.html#starting
-classpath classpath, -cp classpath Specifies a list of directories, JAR files, and ZIP archives to search for class files. Separate class path entries with colons (:). Specifying -classpath or -cp overrides any setting of the CLASSPATH environment variable. If -classpath and -cp are not used and CLASSPATH is not set, then the user class path consists of the current directory (.). As a special convenience, a class path element that contains a base name of * is considered equivalent to specifying a list of all the files in the directory with the extension .jar or .JAR. A Java program cannot tell the difference between the two invocations. For example, if directory mydir contains a.jar and b.JAR, then the class path element mydir/* is expanded to a A.jar:b.JAR, except that the order of jar files is unspecified. All jar files in the specified directory, even hidden ones, are included in the list. A class path entry consisting simply of * expands to a list of all the jar files in the current directory. The CLASSPATH environment variable, where defined, will be similarly expanded. Any class path wildcard expansion occurs before the Java VM is started. No Java program will ever see wild cards that are not expanded except by querying the environment. For example, by calling System.getenv("CLASSPATH").
-Dproperty=value Sets a system property value.
-d32 Run the application in a 32-bit environment. If a 32-bit environment is not installed or is not supported, an error will be reported. By default, the application is run in a 32-bit environment unless a 64-bit only system is used.
-d64 Run the application in a 64-bit environment. If a 64-bit environment is not installed or is not supported, an error will be reported. By default, the application is run in a 32-bit environment unless a 64-bit only system is used. Currently only the Java HotSpot Server VM supports 64-bit operation, and the -server option is implicit with the use of -d64. The -client option is ignored with the use of -d64. This is subject to change in a future release.
-disableassertions[:package name"..." | :class name ], -da[:package name"..." | :class name ] Disable assertions. This is the default. With no arguments, -disableassertions or -da disables assertions. With one argument ending in "...", the switch disables assertions in the specified package and any subpackages. If the argument is "...", then the switch disables assertions in the unnamed package in the current working directory. With one argument not ending in "...", the switch disables assertions in the specified class. To run a program with assertions enabled in package com.wombat.fruitbat but disabled in class com.wombat.fruitbat.Brickbat, the following command could be used: java -ea:com.wombat.fruitbat... -da:com.wombat.fruitbat.Brickbat <Main Class> The -disableassertions and -da switches apply to all class loaders and to system classes (which do not have a class loader). There is one exception to this rule: in their no-argument form, the switches do not apply to system. This makes it easy to turn on asserts in all classes except for system classes. The -disablesystemassertions option provides a separate swith to enable assertions in all system classes.
-enableassertions[:package name"..." | :class name ], -ea[:package name"..." | :class name ] Enable assertions. Assertions are disabled by default. With no arguments, -enableassertions or -ea enables assertions. With one argument ending in "...", the switch enables assertions in the specified package and any subpackages. If the argument is "...", then the switch enables assertions in the unnamed package in the current working directory. With one argument not ending in "...", the switch enables assertions in the specified class. If a single command contains multiple instances of these switches, then they are processed in order before loading any classes. So, for example, to run a program with assertions enabled only in package com.wombat.fruitbat (and any subpackages), the following command could be used: java -ea:com.wombat.fruitbat... <Main Class> The -enableassertions and -ea switches apply to all class loaders and to system classes (which do not have a class loader). There is one exception to this rule: in their no-argument form, the switches do not apply to system. This makes it easy to turn on asserts in all classes except for system classes. The -enablesystemassertions option provides a separate switch to enable assertions in all system classes.
-enablesystemassertions, -esa Enable assertions in all system classes (sets the default assertion status for system classes to true).
-disablesystemassertions, -dsa Disables assertions in all system classes.
-help or -? Displays usage information and exit.
-jar Executes a program encapsulated in a JAR file. The first argument is the name of a JAR file instead of a startup class name. For this option to work, the manifest of the JAR file must contain a line in the form Main-Class: classname. Here, classname identifies the class with the public static void main(String[] args) method that serves as your application's starting point. When you use this option, the JAR file is the source of all user classes, and other user class path settings are ignored. JAR files that can be run with the java -jar option can have their execute permissions set so they can be run without using java -jar. See JAR File Overview at http://docs.oracle.com/javase/7/docs/technotes/guides/jar/jarGuide.html
-javaagent:jarpath[=options] Loads a Java programming language agent. For more information about instrumenting Java applications, see the java.lang.instrument package description in the Java API documentation at http://docs.oracle.com/javase/7/docs/api/java/lang/instrument/package-summary.html @ http://docs.oracle.com/javase/7/docs/api/java/lang/instrument/package-summary.html
-jre-restrict-search Includes user-private JREs in the version search.
-no-jre-restrict-search Excludes user-private JREs in the version search.
-showversion Displays version information and continues.
-splash:imagepath Shows splash screen with image specified by imagepath.
-verbose, -verbose:class Displays information about each class loaded.
-verbose:gc Reports on each garbage collection event.
-verbose:jni Reports information about use of native methods and other Java Native Interface activity.
-version Displays version information and exits. See also the -showversion option.
-version:release Specifies that the version specified by the release is required by the class or JAR file specified on the command line. If the version of the java command called does not meet this specification and an appropriate implementation is found on the system, then the appropriate implementation will be used. The release option specifies an exact version and a list of versions called a version string. A version string is an ordered list of version ranges separated by spaces. A version range is either a version-id, a version-id followed by an asterisk (*), a version-id followed by a plus sign (+), or a version range that consists of two version-ids combined using an ampersand (&). The asterisk means prefix match, the plus sign means this version or greater, and the ampersand means the logical and of the two version-ranges, for example: -version:"1.6.0_13 1.6*&1.6.0_10+" The meaning of the previous example is that the class or JAR file requires either version 1.6.0_13, or a version with 1.6 as a version-id prefix and that is not less than 1.6.0_10. The exact syntax and definition of version strings can be found in Appendix A of the Java Network Launching Protocol & API Specification (JSR-56). For JAR files, the preference is to specify version requirements in the JAR file manifest rather than on the command line. See Notes for important policy information on the use of this option.
Non-Standard Options -X Displays information about nonstandard options and exits.
-Xint Operates in interpreted-only mode. Compilation to native code is disabled, and all bytecode is executed by the interpreter. The performance benefits offered by the Java HotSpot Client VM adaptive compiler is not present in this mode.
-Xbatch Disables background compilation. Typically, the Java VM compiles the method as a background task, running the method in interpreter mode until the background compilation is finished. The -Xbatch flag disables background compilation so that compilation of all methods proceeds as a foreground task until completed.
-Xbootclasspath:bootclasspath Specifies a colon-separated list of directories, JAR files, and ZIP archives to search for boot class files. These are used in place of the boot class files included in the Java platform JDK. Applications that use this option for the purpose of overriding a class in rt.jar should not be deployed because doing so would contravene the Java Runtime Environment binary code license.
-Xbootclasspath/a:path Specifies a colon-separated path of directories, JAR files, and ZIP archives to append to the default bootstrap class path.
-Xbootclasspath/p:path Specifies a colon-separated path of directories, JAR files, and ZIP archives to add in front of the default bootstrap class path. Do not deploy applications that use this option to override a class in rt.jar because this violates the Java Runtime Environment binary code license.
-Xcheck:jni Performs additional checks for Java Native Interface (JNI) functions. Specifically, the Java Virtual Machine validates the parameters passed to the JNI function and the runtime environment data before processing the JNI request. Any invalid data encountered indicates a problem in the native code, and the Java Virtual Machine will terminate with a fatal error in such cases. Expect a performance degradation when this option is used.
-Xfuture Performs strict class-file format checks. For backward compatibility, the default format checks performed by the Java virtual machine are no stricter than the checks performed by 1.1.x versions of the JDK software. The -Xfuture option turns on stricter class-file format checks that enforce closer conformance to the class-file format specification. Developers are encouraged to use this flag when developing new code because the stricter checks will become the default in future releases of the Java application launcher.
-Xnoclassgc Disables class garbage collection. Use of this option preven memory recovery from loaded classes thus increasing overall memory usage. This could cause OutOfMemoryError to be thrown in some applications.
-Xincgc Enables the incremental garbage collector. The incremental garbage collector, which is turned off by default, will reduce the occasional long garbage-collection pauses during program execution. The incremental garbage collector will at times execute concurrently with the program and during such times will reduce the processor capacity available to the program.
-Xloggc:file Reports on each garbage collection event, as with -verbose:gc, but logs this data to a file. In addition to the information -verbose:gc gives, each reported event will be preceded by the time (in seconds) since the first garbage-collection event. Always use a local file system for storage of this file to avoid stalling the Java VM due to network latency. The file may be truncated in the case of a full file system and logging will continue on the truncated file. This option overrides -verbose:gc when both are specified on the command line.
-Xmnsize or -XX:NewSize Sets the size of the young generation (nursery).
-Xmsn Specifies the initial size, in bytes, of the memory allocation pool. This value must be a multiple of 1024 greater than 1 MB. Append the letter k or K to indicate kilobytes, or m or M to indicate megabytes. The default value is chosen at runtime based on system configuration. See Garbage Collector Ergonomics at http://docs.oracle.com/javase/7/docs/technotes/guides/vm/gc-ergonomics.html Examples: -Xms6291456 -Xms6144k -Xms6m
-Xmxn Specifies the maximum size, in bytes, of the memory allocation pool. This value must a multiple of 1024 greater than 2 MB. Append the letter k or K to indicate kilobytes, or m or M to indicate megabytes. The default value is chosen at runtime based on system configuration. For server deployments, -Xms and -Xmx are often set to the same value. See Garbage Collector Ergonomics at http://docs.oracle.com/javase/7/docs/technotes/guides/vm/gc-ergonomics.html Examples: -Xmx83886080 -Xmx81920k -Xmx80m On Solaris 7 and Solaris 8 SPARC platforms, the upper limit for this value is approximately 4000 m minus overhead amounts. On Solaris 2.6 and x86 platforms, the upper limit is approximately 2000 m minus overhead amounts. On Linux platforms, the upper limit is approximately 2000 m minus overhead amounts.
-Xprof Profiles the running program, and sends profiling data to standard output. This option is provided as a utility that is useful in program development and is not intended to be used in production systems.
-Xrs Reduces use of operating-system signals by the Java VM. In an earlier release, the Shutdown Hooks facility was added to enable orderly shutdown of a Java application. The intent was to enable user cleanup code (such as closing database connections) to run at shutdown, even if the Java VM terminates abruptly. The Java VM catches signals to implement shutdown hooks for unexpected Java VM termination. The Java VM uses SIGHUP, SIGINT, and SIGTERM to initiate the running of shutdown hooks. The JVM uses a similar mechanism to implement the feature of dumping thread stacks for debugging purposes. The JVM uses SIGQUIT to perform thread dumps. Applications embedding the Java VM frequently need to trap signals such as SIGINT or SIGTERM, which can lead to interference with the Java VM signal handlers. The -Xrs command-line option is available to address this issue. When -Xrs is used on the Java VM, the signal masks for SIGINT, SIGTERM, SIGHUP, and SIGQUIT are not changed by the Java VM, and signal handlers for these signals are not installed. There are two consequences of specifying -Xrs:
o SIGQUIT thread dumps are not available.
o User code is responsible for causing shutdown hooks to run, for example by calling System.exit() when the Java VM is to be terminated.
-Xssn Sets the thread stack size.
-XX:AllocationPrefetchStyle=n Sets the style of prefetch used during allocation. default=2.
-XX:+AggressiveOpts Enables aggressive optimization.
-XX:+|-DisableAttachMechanism Specifies whether commands (such as jmap and jconsole) can attach to the Java VM. By default, this feature is disabled. That is, attaching is enabled, for example: java -XX:+DisableAttachMechanism
-XXLargePageSizeInBytes=n Specifies the maximum size for large pages.
-XX:MaxGCPauseMillis=n Sets a target for the maximum GC pause time. This is a soft goal, and the Java VM will make its best effort to achieve it. There is no maximum value set by default.
-XX:NewSize Sets the size of the young generation (nursery). Sames as -Xmnsize.
-XX:ParallelGCThreads=n Sets the number of GC threads in the parallel collectors.
-XX:PredictedClassLoadCount=n This option requires that the UnlockExperimentalVMOptions flag be set first. Use the PredictedClassLoadCount flag if your application loads a lot of classes and especially if class.forName() is used heavily. The recommended value is the number of classes loaded as shown in the output from -verbose:class. Example: java -XX:+UnlockExperimentalVMOptions -XX:PredictedClassLoadCount=60013
-XX:+PrintCompilation Prints verbose output from the Java HotSpot VM dynamic runtime compiler.
-XX:+PrintGCDetails -XX:+PrintGCTimeStamps Prints garbage collection output along with time stamps.
-XX:SoftRefLRUPolicyMSPerMB=0 This flag enables aggressive processing of software references. Use this flag if the software reference count has an impact on the Java HotSpot VM garbage collector.
-XX:TLABSize=n Thread local allocation buffers (TLAB) are enabled by default in the Java HotSpot VM. The Java HotSpot VM sizes TLABs based on allocation patterns. The -XX:TLABSize option enables fine-tuning the size of TLABs.
-XX:+UseAltSigs The Java VM uses SIGUSR1 and SIGUSR2 by default, which can sometimes conflict with applications that signal-chain SIGUSR1 and SIGUSR2. The -XX:+UseAltSigs option causes the Java VM to use signals other than SIGUSR1 and SIGUSR2 as the default.
-XX:+|-UseCompressedOops Enables compressed references in 64-bit Java VMs. This option is true by default.
-XX:+UseConcMarkSweepGC or -XX:+UseG1GC Enables either the Concurrent Mark Sweep (CMS) or the G1 garbage collectors.
-XX:+|-UseLargePages Enables large page support. Large pages are enabled by default on Solaris.
-XX:+UseParallelOldGC Enables the parallel garbage collectors, which are optimized for throughput and average response time.
The -version:release option places no restrictions on the complexity of the release specification. However, only a restricted subset of the possible release specifications represent sound policy and only these are fully supported. These policies are:
1. Any version, represented by not using this option.
2. Any version greater than an arbitrarily precise version-id value, for example: "1.6.0_10+" This would utilize any version greater than 1.6.0_10. This is useful for a case where an interface was introduced (or a bug fixed) in the release specified.
3. A version greater than an arbitrarily precise version-id, bounded by the upper bound of that release family, for example: "1.6.0_10+&1.6*"
4. An or expressions of items 2 or 3, for example: "1.6.0_10+&1.6* 1.7+" Similar to item 2. This is useful when a change was introduced in a release (1.7) but also made available in updates to earlier releases.
Performance Tuning Examples The following examples show how to use experimental tuning flags to optimize either throughput or faster response time.
Example 1, Tuning for Higher Throughput java -d64 -server -XX:+AggressiveOpts -XX:+UseLargePages -Xmn10g  -Xms26g -Xmx26g
Example 2, Tuning for Lower Response Time java -d64 -XX:+UseG1GC -Xms26g Xmx26g -XX:MaxGCPauseMillis=500 -XX:+PrintGCTimeStamps
The following exit values are typically returned by the launcher, typically when the launcher is called with the wrong arguments, serious errors, or exceptions thrown from the Java Virtual Machine. However, a Java application may choose to return any value using the API call System.exit(exitValue).
o 0: Successful completion
o >0: An error occurred
o javac(1)
o jdb(1)
o javah(1)
o jar(1)
BMAPTOOL(1)                       User Commands                      BMAPTOOL(1)
bmaptool - create block map (bmap) for a file or copy a file using bmap
bmaptool [--help] [--version] [--quiet] [--debug] <command> [<options>] <args>
Bmaptool is a generic tool for creating the block map (bmap) for a file and copying files using the block map. The idea is that large files, like raw system image files, can be copied or flashed a lot faster with bmaptool than with traditional tools, like "dd" or "cp".
Bmaptool supports 2 commands: 1. copy - copy a file to another file using bmap or flash an image to a block device 2. create - create a bmap for a file
Please, find full documentation for the project online.
--version Print bmaptool version and exit.
-h, --help Print short help text and exit.
-q, --quiet Be quiet, do not print extra information.
-d, --debug Print debugging messages.
copy [options] IMAGE DEST Copy file IMAGE to the destination regular file or block device DEST using bmap. IMAGE may either be a local path or an URL. DEST may either be a regular file or a block device (only local).
Unless the bmap file is explicitly specified with the "--bmap" option, bmaptool automatically discovers it by looking for a file with the same basename as IMAGE but with the ".bmap" extension. The bmap file is only looked for in IMAGE's directory (or base URL, in case IMAGE was specified as an URL). If the bmap file is not found, bmaptool fails. To copy without bmap, use the "--nobmap" option.
Both IMAGE and the bmap file may be specified as an URL (http://, ftp://, https://, file://, ssh://). In order to make bmaptool use a proxy server, please, specify the proxy using the standard "$http_proxy", "$https_proxy", "$ftp_proxy" or "$no_proxy" environment variables.
If the server requires authentication, user name and password may be specified in the URL, for example "https://user:password@my.server.org/image.raw.bz2", or "ssh://user:password@host:path/to/image.raw".
IMAGE may be compressed, in which case bmaptool decompresses it on-the- fly.  The compression type is detected by the file extension and the following extensions are supported:
1. ".gz", ".gzip", ".tar.gz" and ".tgz" for files and tar archives compressed with "gzip" program 2. ".bz2", "tar.bz2", ".tbz2", ".tbz", and ".tb2" for files and tar archives compressed with "bzip2" program 3. ".xz", ".tar.xz", ".txz" for files and tar archives compressed with "xz" program 4. ".lzo", "tar.lzo", ".tzo" for files and tar archives compressed with "lzo" program 4. ".lz4", "tar.lz4", ".tlz4" for files and tar archives compressed with "lz4" program
IMAGE files with other extensions are assumed to be uncompressed. Note, bmaptool uses "pbzip2" and "pigz" programs for decompressing bzip2 and gzip archives faster, unless they are not available, in which case if falls-back to using "bzip2" and "gzip".
If DEST is a block device node (e.g., "/dev/sdg"), bmaptool opens it in exclusive mode. This means that it will fail if any other process has IMAGE block device node opened. This also means that no other processes will be able to open IMAGE until bmaptool finishes the copying. Please, see semantics of the "O_EXCL" flag of the "open()" syscall.
The bmap file typically contains SHA-256 checksum for itself as well as SHA-256 checksum for all the mapped data regions, which makes it possible to guarantee data integrity. bmaptool verifies the checksums and exits with an error in case of a mismatch. Checksum verification can be disabled using the "--no-verify" option. bmaptool does not verify that unampped areas contain only zeroes, because these areas are anyway dropped and are not used for anything.
The bmap file may be signed with OpenPGP (gpg). The signature may be either detached (a separate file) or "built into" the bmap file (so called "clearsign" signature).
The detached signature can be specified with the "--bmap-sig" option, otherwise bmaptool tries to automatically discover it by looking for a file with the same basename as the bmap file but with the ".asc" or ".sig" extension.  This is very similar to the bmap file auto- discovery. So if a ".asc" or ".sig" file exists, bmaptool will verify the signature.
The clearsign signature is part of the bmap file and bmaptool automatically detected and verifies it.
If the signature is bad, bmaptool exits with an error. Bmap file signature verification can be disabled using the "--no-sig-verify" option.
OPTIONS -h, --help Print short help text about the "copy" command and exit.
--bmap BMAP Use bmap file "BMAP" for copying. If this option is not specified, bmaptool tries to automatically discover the bmap file.
--bmap-sig SIG Use a detached OpenPGP signature file "SIG" for verifying the bmap file integrity and publisher. If this option is not specified, bmaptool tries to automatically discover the signature file.
--nobmap Disable automatic bmap file discovery and force flashing entire IMAGE without bmap.
--no-verify Do not verify data checksums when copying (not recommended). The checksums are stored in the bmap file, and normally bmaptool verifies that the data in IMAGE matches the checksums.
--no-sig-verify Do not verify the OpenPGP bmap file signature (not recommended).
EXAMPLES bmaptool copy image.raw.bz2 /dev/sdg Copy bz2-compressed local file "image.raw.bz2" to block device "/dev/sdg". The image file is uncompressed on-the-fly. The bmap file is discovered automatically. The OpenPGP signature is detected/discovered automatically too.
bmaptool copy http://my-server.com/files/image.raw.bz2 $HOME/tmp/file Copy bz2-compressed remote "image.raw.bz2" to regular file "$HOME/tmp/file".  The image file is uncompressed on-the-fly. The bmap file is discovered automatically. The OpenPGP signature is detected/discovered automatically too.
bmaptool copy --bmap image.bmap --bmap-sig image.bmap.asc image.raw /dev/sdg Copy non-compressed local file "image.raw" to block device "/dev/sdg" using bmap file "image.bmap". Verify the bmap file signature using a detached OpenPGP signature from "imag.bmap.asc".
create [options] IMAGE Generate bmap for a regular file IMAGE. Internally, this command uses the Linux "FIEMAP" ioctl to find out which IMAGE blocks are mapped. However, if "FIEMAP" is not supported, the "SEEK_HOLE" feature of the "lseek" system call is used instead. By default, the resulting bmap file is printed to stdout, unless the "--output" option is used.
The IMAGE file is always synchronized before the block map is generated. And it is important to make sure that the IMAGE file is not modified when the bmap file is being generated, and after the bmap file has been generated. Otherwise the bmap file becomes invalid and checksum verification will fail.
The image file can further be signed using OpenPGP.
OPTIONS -h, --help Print short help text about the "create" command and exit.
-o, --output OUTPUT Save the generated bmap in the OUTPUT file (by default the bmap is printed to stdout).
--no-checksum Generate a bmap file without SHA1 checksums (not recommended).
EXAMPLES bmaptool create image.raw Generate bmap for the "image.raw" file and print it to stdout.
bmaptool create -o image.bmap image.raw Generate bmap for the "image.raw" file and save it in "image.bmap".
Artem Bityutskiy <artem.bityutskiy@linux.intel.com>.
Please, report bugs to Artem Bityutskiy <artem.bityutskiy@linux.intel.com> or to the bmap-tools mailing list <bmap-tools@lists.infradead.org>.
HOSTID(1)                         User Commands                        HOSTID(1)
hostid - print the numeric identifier for the current host
hostid [OPTION]
Print the numeric identifier (in hexadecimal) for the current host.
gethostid(3)
Full documentation <https://www.gnu.org/software/coreutils/hostid> or available locally via: info '(coreutils) hostid invocation'
MPG321(1)                    General Commands Manual                   MPG321(1)
mpg321 â€” Simple and lightweight command line MP3 player
mpg321 [options] file(s) | URL(s) | -
mpg321 is a free command-line mp3 player, which uses the mad audio decoding library. mpg321 was written to be a drop-in replacement for the (by-then) non-free mpg123 player.  Some functions remain unimplemented, but mpg321 should function as a basic drop-in replacement for mpg123 front-ends such as gqmpeg, and those programs which use mpg123 to decode mp3 files (like gtoaster, and other CD-recording software).
-o devicetype Set the output device type to devicetype.  devicetype can be one of:
oss - the Linux Open Sound System;
sun - the Sun audio system;
alsa - the Advanced Linux Sound Architecture;
alsa09 - the Advanced Linux Sound Architecture, version 0.9;
esd - the Enlightened Sound Daemon;
arts - the analog real-time synthesiser
See -a device, below.
-a device, --audiodevice device Use device for audio-out instead of the default device, depending on the output device you've chosen (via -o devicetype).  By default this is the native sound device. Generally this is the device for devicetype (or the default system device) to use for output (i.e. /dev/sound/dsp1).
This option has no effect with -o arts.
For -o esd, specify the host on which esd is running; defaults to localhost.
For -o alsa, specify audio device using the hw:x,y syntax, where x and y are numbers, default is hw:0,0.  For example, if there is only one device installed, in most cases, the device should be named hw:0,0.  When there is only one device, the device should always have the same name and numbers.
-g N, --gain N Set gain (volume) to N (1-100).
-k N, --skip N Skip N frames into the file being played.
-n N, --frames N Decode only the first N frames of the stream. By default, the entire stream is decoded.
-@ list, --list list Use the file list for a playlist. The list should be in a format of filenames followed by a line feed. Multiple -@ or --list specifiers will be ignored; only the last -@ or --list option will be used. The playlist is concatenated with filenames specified on the command-line to produce one master playlist. A filename of '-' will cause standard input to be read as a playlist.
-z, --shuffle Shuffle playlists and files specified on the command-line. Produces a randomly-sorted playlist which is then played through once.
-Z, --random Randomise playlists and files specified on the command-line. Files are played through, choosing at random; this means that random files will be played for as long as mpg321 is running.
-v, --verbose Be more verbose. Show current byte, bytes remaining, time, and time remaining, as well as more information about the mp3 file.
-s, --stdout Use standard output instead of an audio device for output. Output is in 16-bit PCM, little-endian.
-w N, --wav N Write to wav file N instead of using the audio device. This option will be preferred if --cdr or --au are specified too. Specifying '-' for N will cause the file to be written to standard output.
--cdr N   Write to cdr file N instead of using the audio device. Specifying '-' for N will cause the file to be written to standard output.
--au N    Write to au file N instead of using the audio device. Specifying '-' for N will cause the file to be written to standard output.
-t, --test Test mode; do no output at all.
-q, --quiet Quiet mode; suppress output of mpg123 boilerplate and file and song name.
-B        Read recursively the given directories. Allows you to define only the directory or directories and then mpg321 recursively plays all the songs.
-F        Turn on FFT analysis on PCM data. Remote mode only
-S        Report song to AudioScrobbler (last.fm).
-x        Set xterm title setting
-b        Number of decoded frames for the output buffer.
-K        Enable Basic Keys.
-R        "Remote control" mode. Useful for front-ends. Allows seeking and pausing of mp3 files. See README.remote (in /usr/share/doc/mpg321 on Debian and some other systems.)
-3, --restart Restart "remote shell". Used only when in "Remote control" mode.
--stereo  Force stereo output: duplicates mono stream on second output channel. Useful for output for devices that don't understand mono, such as some CD players.
--aggressive Aggressive mode; try to get higher priority on the system. Needs root permissions.
--skip-printing-frames=N Skip N frames between printing a frame status update, in both Remote Control (-R) and verbose (-v) mode. Can help CPU utilisation on slower machines. This is an mpg321-specific option.
-l N, --loop N Loop song or playlist N times.If N is 0 means infinite times.
--help, --longhelp Show summary of options.
-V, --version Show version of program.
Basic keys: * or /   Increase or decrease volume.
n        Skip song.
m        Mute/unmute.
This manual page was written by Joe Drew <drew@debian.org>.
Maintained by Nanakos Chrysostomos <nanakos@wired-net.gr>.
Permission is granted to copy, distribute and/or modify this document under the terms of the BSD license.  On Debian systems, this can be found in /usr/share/common-licenses/BSD.
SSH-COPY-ID(1)             BSD General Commands Manual            SSH-COPY-ID(1)
ssh-copy-id — use locally available keys to authorise logins on a remote machine
ssh-copy-id [-f] [-n] [-s] [-i [identity_file]] [-p port] [-o ssh_option] [user@]hostname ssh-copy-id -h | -?
ssh-copy-id is a script that uses ssh(1) to log into a remote machine (presumably using a login password, so password authentication should be enabled, unless you've done some clever use of multiple identities).  It assembles a list of one or more fingerprints (as described below) and tries to log in with each key, to see if any of them are already installed (of course, if you are not using ssh-agent(1) this may result in you being repeatedly prompted for pass-phrases).  It then assembles a list of those that failed to log in, and using ssh, enables logins with those keys on the remote server.  By default it adds the keys by appending them to the remote user's ~/.ssh/authorized_keys (creating the file, and directory, if necessary).  It is also capable of detecting if the remote system is a NetScreen, and using its ‘set ssh pka-dsa key ...’ command instead.
-i identity_file Use only the key(s) contained in identity_file (rather than looking for identities via ssh-add(1) or in the default_ID_file).  If the filename does not end in .pub this is added.  If the filename is omitted, the default_ID_file is used.
Note that this can be used to ensure that the keys copied have the comment one prefers and/or extra options applied, by ensuring that the key file has these set as preferred before the copy is attempted.
-f      Forced mode: doesn't check if the keys are present on the remote server.  This means that it does not need the private key.  Of course, this can result in more than one copy of the key being installed on the remote system.
-n      do a dry-run.  Instead of installing keys on the remote system simply prints the key(s) that would have been installed.
-s      SFTP mode: usually the public keys are installed by executing commands on the remote side.  With this option the user's ~/.ssh/authorized_keys file will be downloaded, modified locally and uploaded with sftp.  This option is useful if the server has restrictions on commands which can be used on the remote side.
-h, -?  Print Usage summary
-p port, -o ssh_option These two options are simply passed through untouched, along with their argument, to allow one to set the port or other ssh(1) options, respectively.
Rather than specifying these as command line options, it is often better to use (per-host) settings in ssh(1)'s configuration file: ssh_config(5).
Default behaviour without -i, is to check if ‘ssh-add -L’ provides any output, and if so those keys are used.  Note that this results in the comment on the key being the filename that was given to ssh-add(1) when the key was loaded into your ssh-agent(1) rather than the comment contained in that file, which is a bit of a shame.  Otherwise, if ssh-add(1) provides no keys contents of the default_ID_file will be used.
The default_ID_file is the most recent file that matches: ~/.ssh/id*.pub, (excluding those that match ~/.ssh/*-cert.pub) so if you create a key that is not the one you want ssh-copy-id to use, just use touch(1) on your preferred key's .pub file to reinstate it as the most recent.
If you have already installed keys from one system on a lot of remote hosts, and you then create a new key, on a new client machine, say, it can be difficult to keep track of which systems on which you've installed the new key.  One way of dealing with this is to load both the new key and old key(s) into your ssh-agent(1).  Load the new key first, without the -c option, then load one or more old keys into the agent, possibly by ssh-ing to the client machine that has that old key, using the -A option to allow agent forwarding:
user@newclient$ ssh-add user@newclient$ ssh -A old.client user@oldl$ ssh-add -c ... prompt for pass-phrase ... user@old$ logoff user@newclient$ ssh someserver
now, if the new key is installed on the server, you'll be allowed in unprompted, whereas if you only have the old key(s) enabled, you'll be asked for confirmation, which is your cue to log back out and run
user@newclient$ ssh-copy-id -i someserver
The reason you might want to specify the -i option in this case is to ensure that the comment on the installed key is the one from the .pub file, rather than just the filename that was loaded into your agent.  It also ensures that only the id you intended is installed, rather than all the keys that you have in your ssh-agent(1).  Of course, you can specify another id, or use the contents of the ssh-agent(1) as you prefer.