217 lines
6.1 KiB
Groff
217 lines
6.1 KiB
Groff
'\" t
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.\" Copyright (c) 2012, 2015, Oracle and/or its affiliates. All rights reserved.
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.\"
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.\" Title: jcmd
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.\" Language: English
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.\" Date: 03 March 2015
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.\" SectDesc: Troubleshooting Tools
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.\" Software: JDK 8
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.\" Arch: generic
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.\" Part Number: E38209-04
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.\" Doc ID: JSSOR
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.\"
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.if n .pl 99999
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.TH "jcmd" "1" "03 March 2015" "JDK 8" "Troubleshooting Tools"
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.\" -----------------------------------------------------------------
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.\" * Define some portability stuff
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.\" -----------------------------------------------------------------
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.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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.\" http://bugs.debian.org/507673
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.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
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.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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.ie \n(.g .ds Aq \(aq
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.el .ds Aq '
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.\" -----------------------------------------------------------------
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.\" * set default formatting
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.\" -----------------------------------------------------------------
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.\" disable hyphenation
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.nh
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.\" disable justification (adjust text to left margin only)
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.ad l
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.\" -----------------------------------------------------------------
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.\" * MAIN CONTENT STARTS HERE *
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.\" -----------------------------------------------------------------
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.SH "NAME"
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jcmd \- Sends diagnostic command requests to a running Java Virtual Machine (JVM)\&.
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.SH "SYNOPSIS"
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.sp
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.if n \{\
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.RS 4
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.\}
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.nf
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\fBjcmd\fR [\fB\-l\fR|\fB\-h\fR|\fB\-help\fR]
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.fi
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.if n \{\
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.RE
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.\}
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.sp
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.if n \{\
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.RS 4
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.\}
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.nf
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\fBjcmd\fR \fIpid\fR|\fImain\-class\fR \fBPerfCounter\&.print\fR
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.fi
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.if n \{\
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.RE
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.\}
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.sp
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.if n \{\
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.RS 4
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.\}
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.nf
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\fBjcmd\fR \fIpid\fR|\fImain\-class\fR \fB\-f\fR \fIfilename\fR
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.fi
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.if n \{\
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.RE
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.\}
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.sp
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.if n \{\
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.RS 4
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.\}
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.nf
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\fBjcmd\fR \fIpid\fR|\fImain\-class\fR \fIcommand\fR[ \fIarguments\fR]
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.fi
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.if n \{\
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.RE
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.\}
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.SH "DESCRIPTION"
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.PP
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The
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\fBjcmd\fR
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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\&.
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.if n \{\
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.sp
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.\}
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.RS 4
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.it 1 an-trap
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.nr an-no-space-flag 1
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.nr an-break-flag 1
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.br
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.ps +1
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\fBNote\fR
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.ps -1
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.br
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.TS
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allbox tab(:);
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l.
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T{
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.PP
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To invoke diagnostic commands from a remote machine or with different identifiers, you can use the
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\fBcom\&.sun\&.management\&.DiagnosticCommandMBean\fR
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interface\&. For more information about the
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\fBDiagnosticCommandMBean\fR
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interface, see the API documentation at http://docs\&.oracle\&.com/javase/8/docs/jre/api/management/extension/com/sun/management/DiagnosticCommandMBean\&.html
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T}
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.TE
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.sp 1
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.sp .5v
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.RE
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.PP
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If you run
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\fBjcmd\fR
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without arguments or with the
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\fB\-l\fR
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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
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\fBjcmd\fR
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with the
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\fB\-h\fR
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or
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\fB\-help\fR
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option prints the tool\(cqs help message\&.
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.if n \{\
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.sp
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.\}
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.RS 4
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.it 1 an-trap
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.nr an-no-space-flag 1
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.nr an-break-flag 1
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.br
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.ps +1
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\fBNote\fR
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.ps -1
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.br
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.TS
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allbox tab(:);
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l.
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T{
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.PP
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The
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\fBjcmd\fR
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utility can be used to dynamically interact with Java Flight Recorder (JFR) in a JVM that is already running\&. You can use it to unlock commercial features, enable/start/stop flight recordings, and obtain various status messages from the system\&. For a list of examples, see the Java Flight Recorder Runtime Guide at http://docs\&.oracle\&.com/javacomponents/jmc\&.htm
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T}
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.TE
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.sp 1
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.sp .5v
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.RE
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.PP
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If you specify the processes identifier (\fIpid\fR) or the main class (\fImain\-class\fR) as the first argument,
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\fBjcmd\fR
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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
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\fB0\fR
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as the process identifier\&. Use one of the following as the diagnostic command request:
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.PP
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Perfcounter\&.print
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.RS 4
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Prints the performance counters available for the specified Java process\&. The list of performance counters might vary with the Java process\&.
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.RE
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.PP
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\-f \fIfilename\fR
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.RS 4
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The name of the file from which to read diagnostic commands and send them to the specified Java process\&. Used only with the
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\fB\-f\fR
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option\&. Each command in the file must be written on a single line\&. Lines starting with a number sign (\fB#\fR) are ignored\&. Processing of the file ends when all lines have been read or when a line containing the
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\fBstop\fR
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keyword is read\&.
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.RE
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.PP
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\fIcommand\fR [\fIarguments\fR]
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.RS 4
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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
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\fBhelp\fR
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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
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\fBhelp\fR
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command\&.
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.sp
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\fBNote:\fR
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If any arguments contain spaces, you must surround them with single or double quotation marks (\fB\*(Aq\fR
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or
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\fB"\fR)\&. In addition, you must escape single or double quotation marks with a backslash (\fB\e\fR) 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)\&.
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.RE
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.SH "OPTIONS"
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.PP
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Options are mutually exclusive\&.
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.PP
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\-f \fIfilename\fR
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.RS 4
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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 (\fB#\fR) are ignored\&. Processing of the file ends when all lines have been read or when a line containing the
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\fBstop\fR
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keyword is read\&.
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.RE
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.PP
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\-h
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.br
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\-help
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.RS 4
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Prints a help message\&.
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.RE
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.PP
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\-l
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.RS 4
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Prints the list of running Java processes identifiers with the main class and command\-line arguments\&.
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.RE
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.SH "SEE ALSO"
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.sp
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.RS 4
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.ie n \{\
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\h'-04'\(bu\h'+03'\c
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.\}
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.el \{\
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.sp -1
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.IP \(bu 2.3
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.\}
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jps(1)
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.RE
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.br
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'pl 8.5i
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'bp
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