# phpman > man > jcmd(1)

[jcmd(1)](https://www.chedong.com/phpMan.php/man/jcmd/1/markdown)                                 Troubleshooting Tools                                [jcmd(1)](https://www.chedong.com/phpMan.php/man/jcmd/1/markdown)



## NAME
       jcmd - Sends diagnostic command requests to a running Java Virtual Machine (JVM).

## SYNOPSIS
           **jcmd** [**-l**|**-h**|**-help**]

           **jcmd** _pid_|_main-class_ **PerfCounter.print**

           **jcmd** _pid_|_main-class_ **-f** _filename_

           **jcmd** _pid_|_main-class_ _command_[ _arguments_]

## DESCRIPTION
       The **jcmd** utility is used to send diagnostic command requests to the JVM. It must be used on
       the same machine on which the JVM is running, and have the same effective user and group
       identifiers that were used to launch the JVM.

           **Note**
           ┌────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
           │                                                                                                                            │
           │           To invoke diagnostic commands from a                                                                             │
           │           remote machine or with different                                                                                 │
           │           identifiers, you can use the                                                                                     │
           │           **com.sun.management.DiagnosticCommandMBean**                                                                        │
           │           interface. For more information about                                                                            │
           │           the **DiagnosticCommandMBean** interface,                                                                            │
           │           see the API documentation at                                                                                     │
           │           <http://docs.oracle.com/javase/8/docs/jre/api/management/extension/com/sun/management/DiagnosticCommandMBean.html> │
           └────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘

       If you run **jcmd** without arguments or with the **-l** option, it prints the list of running Java
       process identifiers with the main class and command-line arguments that were used to launch
       the process. Running **jcmd** with the **-h** or **-help** option prints the tool’s help message.

       If you specify the processes identifier (_pid_) or the main class (_main-class_) as the first
       argument, **jcmd** sends the diagnostic command request to the Java process with the specified
       identifier or to all Java processes with the specified name of the main class. You can also
       send the diagnostic command request to all available Java processes by specifying **0** as the
       process identifier. Use one of the following as the diagnostic command request:

       Perfcounter.print
           Prints the performance counters available for the specified Java process. The list of
           performance counters might vary with the Java process.

       -f _filename_
           The name of the file from which to read diagnostic commands and send them to the
           specified Java process. Used only with the **-f** option. Each command in the file must be
           written on a single line. Lines starting with a number sign (**#**) are ignored. Processing
           of the file ends when all lines have been read or when a line containing the **stop** keyword
           is read.

       _command_ [_arguments_]
           The command to be sent to the specified Java process. The list of available diagnostic
           commands for a given process can be obtained by sending the **help** command to this process.
           Each diagnostic command has its own set of arguments. To see the description, syntax, and
           a list of available arguments for a command, use the name of the command as the argument
           for the **help** command.

           **Note:** If any arguments contain spaces, you must surround them with single or double
           quotation marks (**'** or **"**). In addition, you must escape single or double quotation marks
           with a backslash (**\**) to prevent the operating system shell from processing quotation
           marks. Alternatively, you can surround these arguments with single quotation marks and
           then with double quotation marks (or with double quotation marks and then with single
           quotation marks).

## OPTIONS
       Options are mutually exclusive.

       -f _filename_
           Reads commands from the specified file. This option can be used only if you specify the
           process identifier or the main class as the first argument. Each command in the file must
           be written on a single line. Lines starting with a number sign (**#**) are ignored.
           Processing of the file ends when all lines have been read or when a line containing the
           **stop** keyword is read.

### -h
### -help
           Prints a help message.

### -l
           Prints the list of running Java processes identifiers with the main class and
           command-line arguments.

## SEE ALSO
       •   [jps(1)](https://www.chedong.com/phpMan.php/man/jps/1/markdown)



JDK 8                                       03 March 2015                                    [jcmd(1)](https://www.chedong.com/phpMan.php/man/jcmd/1/markdown)